281 lines
4.7 KiB
ArmAsm
281 lines
4.7 KiB
ArmAsm
# keypad.s
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# Trevor Barnes
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# CE2801-031
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# Description: Contains routines for the keypad component
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.syntax unified
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.cpu cortex-m4
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.thumb
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.section .text
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.equ RCC_BASE, 0x40023800
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.equ RCC_AHB1ENR, 0x30
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.equ RCC_GPIOCEN, 1<<2
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.equ GPIOC_BASE, 0x40020800
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.equ GPIO_MODER, 0x00
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.equ GPIO_ODR, 0x14
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.equ GPIO_IDR, 0x10
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.equ GPIO_PUPDR, 0x0C
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.equ GPIO_BSRR, 0x18
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# Row 1
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.equ k1, 0xEE
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.equ k2, 0xED
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.equ k3, 0xEB
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.equ k4, 0xE7
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# Row 2
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.equ k5, 0xDE
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.equ k6, 0xDD
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.equ k7, 0xDB
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.equ k8, 0xD7
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# Row 3
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.equ k9, 0xBE
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.equ k10, 0xBD
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.equ k11, 0xBB
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.equ k12, 0xB7
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# Row 4
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.equ k13, 0x7E
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.equ k14, 0x7D
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.equ k15, 0x7B
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.equ k16, 0x77
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.global KeyInit
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# Initialize the keypad GPIO port.
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# Depending on your scanning algorithm,
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# there may not be any work to do in this method
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KeyInit:
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push {r0,r1,r2,lr}
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ldr r1, =RCC_BASE
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ldr r2, [r1, #RCC_AHB1ENR]
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orr r2, r2, #RCC_GPIOCEN
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str r2, [r1, #RCC_AHB1ENR]
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# Read current PUPDR state
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ldr r1, =GPIOC_BASE
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ldr r2, [r1, #GPIO_PUPDR]
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# Modify and write rows and columns to be "Pull-Up"
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bfc r2, #0, #16
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ldr r0, =0x5555
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orr r2, r2, r0
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str r2, [r1, #GPIO_PUPDR]
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pop {r0,r1,r2,pc}
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.global KeyGetKeyNoblock
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# Returns in r0 a numeric code representing
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# the button on the keypad that was pressed (1 to 16),
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# or 0 if no button is pressed
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KeyGetKeyNoblock:
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push {r1,r2,lr}
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bl keypadScan
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mov r1, #0
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ubfx r2, r0, #4, #4
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cmp r2, #0xF
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beq 1f
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add r1, #1
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cmp r0, #k1
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beq 1f
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add r1, #1
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cmp r0, #k2
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beq 1f
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add r1, #1
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cmp r0, #k3
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beq 1f
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add r1, #1
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cmp r0, #k4
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beq 1f
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add r1, #1
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cmp r0, #k5
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beq 1f
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add r1, #1
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cmp r0, #k6
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beq 1f
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add r1, #1
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cmp r0, #k7
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beq 1f
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add r1, #1
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cmp r0, #k8
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beq 1f
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add r1, #1
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cmp r0, #k9
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beq 1f
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add r1, #1
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cmp r0, #k10
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beq 1f
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add r1, #1
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cmp r0, #k11
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beq 1f
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add r1, #1
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cmp r0, #k12
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beq 1f
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add r1, #1
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cmp r0, #k13
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beq 1f
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add r1, #1
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cmp r0, #k14
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beq 1f
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add r1, #1
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cmp r0, #k15
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beq 1f
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add r1, #1
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cmp r0, #k16
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beq 1f
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1:
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mov r0, r1
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pop {r1,r2,pc}
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.global KeyGetKey
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# Same as KeyGetkeyNoblock, but blocks – that is,
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# waits until a key is pressed and then returns the key code.
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# Per discussion in lecture, you may wish to return after said key
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# is released
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KeyGetKey:
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push {r1,r2,r3,lr}
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mov r0, #0
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1:
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mov r1, #10
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bl usDelay
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bl KeyGetKeyNoblock
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cmp r0, #0
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beq 1b
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2:
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# Row = Input | Col = Output
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ldr r1, =GPIOC_BASE
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ldr r2, [r1, #GPIO_MODER]
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mov r3, #0x0055
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bfi r2, r3, #0, #16
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str r2, [r1, #GPIO_MODER]
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# "0000" -> ODR (Col)
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ldrb r2, [r1, #GPIO_ODR]
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mov r3, #0x0
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bfi r2, r3, #0, #4
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strb r2, [r1, #GPIO_ODR]
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# Store input data in r3
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ldrb r3, [r1, #GPIO_IDR]
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cmp r3, #0xF0
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bne 2b
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# Set both back to inputs, (default state)
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@ ldr r1, =GPIOC_BASE
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@ ldr r2, [r1, #GPIO_MODER]
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@ mov r3, #0x0000
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@ bfi r2, r3, #0, #16
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@ str r2, [r1, #GPIO_MODER]
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pop {r1,r2,r3,pc}
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.global KeyGetChar
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# Similar to KeyGetkey, but returns the ASCII code corresponding
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# to the key press.
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# This method blocks. You should use a data structure in .rodata
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# to map keys to characters
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KeyGetChar:
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push {r1,r2,lr}
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bl KeyGetKey
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sub r0, #1
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mov r2, r0
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ldr r1, =keyChars
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ldrb r0, [r1, r2]
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pop {r1,r2,pc}
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# Waits for input on keypad and returns that value in r0
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keypadScan:
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push {r1,r2,r3,lr}
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2:
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# Row = Input | Col = Output
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ldr r1, =GPIOC_BASE
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ldr r2, [r1, #GPIO_MODER]
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mov r0, #0x0055
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bfi r2, r0, #0, #16
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str r2, [r1, #GPIO_MODER]
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# "0000" -> ODR (Col)
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ldrb r2, [r1, #GPIO_ODR]
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mov r3, #0x0
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bfi r2, r3, #0, #4
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strb r2, [r1, #GPIO_ODR]
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# Store input data in r3
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mov r0, r1
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mov r1, #5
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bl usDelay
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mov r1, r0
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ldrb r3, [r1, #GPIO_IDR]
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# R3 = Row IDR
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#ubfx r3, r2, #4, #4
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# Row IDR -> Row ODR
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# ldrb r2, [r1, #GPIO_ODR]
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# orr r2, r2, r3
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# strb r2, [r1, #GPIO_ODR]
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# Delay
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# Row = Output | Col = Input
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ldr r1, =GPIOC_BASE
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ldr r2, [r1, #GPIO_MODER]
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mov r0, #0x5500
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bfi r2, r0, #0, #16
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str r2, [r1, #GPIO_MODER]
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# "0000" -> ODR (Row)
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ldrb r2, [r1, #GPIO_ODR]
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mov r0, #0x0
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bfi r2, r0, #0, #4
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strb r2, [r1, #GPIO_ODR]
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mov r0, r1
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mov r1, #5
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bl usDelay
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mov r1, r0
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# Read IDR (Row & Col)
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ldrb r0, [r1, #GPIO_IDR]
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orr r0, r0, r3
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# Set both back to inputs, (default state)
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@ ldr r1, =GPIOC_BASE
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@ ldr r2, [r1, #GPIO_MODER]
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@ mov r3, #0x0000
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@ bfi r2, r3, #0, #16
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@ str r2, [r1, #GPIO_MODER]
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1:
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pop {r1,r2,r3,pc}
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.section .rodata
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keyChars:
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.asciz "123A456B789C*0#D"
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