VGA not working?
I am trying to give 800x600@56hz vga output with my stm32f103c8t6. For some reason I can't get it to work. Both of the monitors I tried are saying "Input is not supported" or sth along thoose lines.I know that they can work with 800x600@56hz. I have tried other resolutions and I couldn't get any of them to work. In some of my tries I got 800x600 54hz,68hz and 72hz.This happened when I tried to speed up the 640x480@60hz numbers but I couldn't get the desired resolution and the other random ones I got were inconsistent. Here is my code:
.thumb
.syntax unified
.equ GPIOB,0x40010C00
.equ GPIOA,0x40010800
.equ RCC ,0x40021000
.equ TIM3 ,0x40000400
.equ TIM2 ,0x40000000
.equ NVIC ,0xE000E100
.equ DMA1 ,0x40020000
.type ramres,%function
.global ramres
ramres:
mov R1,0
ldr R0,=0x20000000
ldr R2,=0x20005000
ramres1:
str R1,[R0],4
cmp R0,R2
bne ramres1
bx lr
.size ramres,.-ramres
.global main
main:
ldr R0,=RCC
mov R1,15
str R1,[R0,0x14] //set the DMA1 Clock || RCC_AHBENR
mov R1,0b1100
str R1,[R0,0x18] //set the GPIOB,GPIOA Clocks || RCC_APB2ENR
mov R1,0b11
str R1,[R0,0x1C] //set the TIM2 and TIM3 Clocks || RCC_APB1ENR
add lr,pc,5
b ramres
mov R0,0x20000000
mov R1,896
strh R1,[R0]
mov R1,824
strh R1,[R0,0x2]
ldr R1,=601
strh R1,[R0,0x4]
add R1,R1,2
strh R1,[R0,0x6]
ldr R0,=DMA1
mov R1,2
str R1,[R0,0x84] //NDT = 2 || DMA1_CNDTR7
ldr R1,=0x40000034 // TIM2_CCR1
str R1,[R0,0x88] // DMA1_CPAR7ldr R2,=TIM2
mov R1,0x20000000
str R1,[R0,0x8C] // DMA1_CMAR7
ldr R1,=13745 //0 11 01 01 1 0 1 1 0 0 0 1
str R1,[R0,0x80] //configuring channel7 || DMA1_CRR7
mov R1,1
str R1,[R0,0x34] //NDT = 1 || DMA1_CNDTR3
str R1,[R0,0x70] //NDT = 1 || DMA1_CNDTR6
ldr R1,=0x4000043C // TIM3_CCR3
str R1,[R0,0x38] // DMA1_CPAR3
str R1,[R0,0x74] // DMA1_CPAR6
ldr R1,=0x20000004
str R1,[R0,0x78] // DMA1_CMAR6
add R1,R1,2
str R1,[R0,0x3C] // DMA1_CMAR3
ldr R1,=13617 //0 11 01 01 0 0 1 1 0 0 0 1
str R1,[R0,0x30] //configuring channel3 || DMA1_CCR3
str R1,[R0,0x6C] //configuring channel6 || DMA1_CCR6
//channel 6 -> tim3 channel 1
//channel 3 -> tim3 channel 4
//PB0 -> tim3 channel 3
//tim2 will be prescaler for tim3
ldr R0,=TIM2
mov R1,1
str R1,[R0,0x28] //set the prescaler to 1 || TIM2_PSC
mov R1,1024
str R1,[R0,0x2C] //set the ARR to 1024 || TIM2_ARR
mov R1,824
str R1,[R0,0x34] //set the CCR1 to 824 || TIM2_CCR1
mov R1,840
str R1,[R0,0x38] //set the CCR2 to 840 || TIM2_CCR2 (CCR1 -> 896)
ldr R1,=920
str R1,[R0,0x40] //set the CCR4 to 920 || TIM2_CCR4 (CCR1 -> 824)
mov R1,0b1
str R1,[R0,0x20] //enable the CC1|| TIM2_CCER
mov R1,0x30
str R1,[R0,0x18] //set OC1M to 011(toggle) || TIM2_CCMR1
mov R1,5120
str R1,[R0,0x0C] //enable the DMA's || TIM2_DIER
mov R1,32
str R1,[R0,0x04] //set MMS to 010 || TIM2_CR2
mov R1,0b01
str R1,[R0] //enable the counter || TIM2_CR1
ldr R0,=TIM3
ldr R1,=625
str R1,[R0,0x2C] //set the ARR to 625 || TIM3_ARR
ldr R1,=605
str R1,[R0,0x34] //set the CCR1 to 605 || TIM3_CCR1 (CCR3 -> 601)
ldr R1,=601
str R1,[R0,0x3C] //set the CCR3 to 601 || TIM3_CCR3
ldr R1,=602
str R1,[R0,0x40] //set the CCR4 to 602 || TIM3_CCR4 (CCR3 -> 603)
mov R1,256
str R1,[R0,0x20] //enable the CC3|| TIM3_CCER
mov R1,0x30
str R1,[R0,0x1C] //set OC3M to 011(toggle) || TIM3_CCMR2
mov R1,4608
str R1,[R0,0x0C] //enable the DMA's || TIM3_DIER
mov R1,23
str R1,[R0,0x08] //TS = 001 SMS = 111 || TIM3_SMCR
mov R1,0b01
str R1,[R0] //enable the counter || TIM3_CR1
ldr R0,=GPIOB
ldr R1,=0x44444444B
str R1,[R0]
ldr R0,=GPIOA
ldr R1,=0x4222222B
str R1,[R0]
wow:
b wowI can confirm that the MCU is running at 72mhz. The PA0 is connected to HSYNC and PB0 is connected to VSYNC. PA1to6 are connected to an DAC that I made with resistors but for now they are irrelevant. I would really appreciate anyone that can help cause I have no idea why this is not working