forked from Github_Repos/cvw
174 lines
2.3 KiB
ArmAsm
174 lines
2.3 KiB
ArmAsm
PERIOD = 22000000
|
|
#PERIOD = 100
|
|
|
|
.section .init
|
|
.global _start
|
|
.type _start, @function
|
|
|
|
|
|
_start:
|
|
# Initialize global pointer
|
|
.option push
|
|
.option norelax
|
|
1:auipc gp, %pcrel_hi(__global_pointer$)
|
|
addi gp, gp, %pcrel_lo(1b)
|
|
.option pop
|
|
|
|
li x1, 0
|
|
li x2, 0
|
|
li x4, 0
|
|
li x5, 0
|
|
li x6, 0
|
|
li x7, 0
|
|
li x8, 0
|
|
li x9, 0
|
|
li x10, 0
|
|
li x11, 0
|
|
li x12, 0
|
|
li x13, 0
|
|
li x14, 0
|
|
li x15, 0
|
|
li x16, 0
|
|
li x17, 0
|
|
li x18, 0
|
|
li x19, 0
|
|
li x20, 0
|
|
li x21, 0
|
|
li x22, 0
|
|
li x23, 0
|
|
li x24, 0
|
|
li x25, 0
|
|
li x26, 0
|
|
li x27, 0
|
|
li x28, 0
|
|
li x29, 0
|
|
li x30, 0
|
|
li x31, 0
|
|
|
|
|
|
# start by writting the clock divider to 4 setting SDC to 25MHz
|
|
la x3, 0x12100
|
|
li x4, -4
|
|
sw x4, 0x0(x3)
|
|
|
|
# start by writting the clock divider to 1 setting SDC to 100MHZ
|
|
la x3, 0x12100
|
|
li x4, 1
|
|
sw x4, 0x0(x3)
|
|
|
|
|
|
# wait until the SDC is done with initialization
|
|
li x4, 0x1
|
|
wait_sdc_done_init:
|
|
lw x5, 4(x3)
|
|
and x5, x5, x4
|
|
bne x5, x4, wait_sdc_done_init
|
|
|
|
# now that it is done lets setup for a read
|
|
li x6, 0x20000000
|
|
sd x6, 0x10(x3) # write address register
|
|
|
|
# send read by writting to command register
|
|
li x7, 0x4
|
|
sw x7, 0xC(x3)
|
|
|
|
li x4, 0x2
|
|
wait_sdc_done_read:
|
|
lw x5, 4(x3)
|
|
and x5, x5, x4
|
|
beq x5, x4, wait_sdc_done_read
|
|
|
|
# copy data from mailbox
|
|
copy_sdc:
|
|
li x8, 512
|
|
li x9, 0
|
|
ld x10, 0x18(x3) # read the mailbox
|
|
addi x9, x9, 1
|
|
blt x8, x9, copy_sdc
|
|
|
|
|
|
|
|
# write to gpio
|
|
li x2, 0xFF
|
|
la x3, 0x10012000
|
|
|
|
# +8 is output enable
|
|
# +C is output value
|
|
|
|
addi x4, x3, 8
|
|
addi x5, x3, 0xC
|
|
|
|
# write initial value of 0xFF to GPO
|
|
sw x2, 0x0(x5)
|
|
# enable output
|
|
sw x2, 0x0(x4)
|
|
|
|
# before jumping to led loop
|
|
# lets try writting to dram.
|
|
|
|
li x21, 0
|
|
li x23, 4096*16 # 64KB of data
|
|
|
|
li x22, 0x80000000
|
|
li x24, 0
|
|
|
|
write_loop:
|
|
add x25, x22, x24
|
|
sw x24, 0(x25)
|
|
addi x24, x24, 4
|
|
blt x24, x23, write_loop
|
|
|
|
li x24, 0
|
|
read_loop:
|
|
add x25, x22, x24
|
|
lw x21, 0(x25)
|
|
|
|
# check value
|
|
bne x21, x24, fail_loop
|
|
|
|
addi x24, x24, 4
|
|
|
|
#
|
|
blt x24, x23, read_loop
|
|
|
|
|
|
|
|
loop:
|
|
|
|
# delay
|
|
li x20, PERIOD
|
|
delay1:
|
|
addi x20, x20, -1
|
|
bge x20, x0, delay1
|
|
|
|
# new GPO
|
|
addi x2, x2, 1
|
|
sw x2, 0x0(x5)
|
|
|
|
j loop
|
|
|
|
|
|
fail_loop:
|
|
|
|
# delay
|
|
li x20, PERIOD/20
|
|
fail_delay1:
|
|
addi x20, x20, -1
|
|
bge x20, x0, fail_delay1
|
|
|
|
# clear GPO
|
|
sw x0, 0x0(x5)
|
|
|
|
# delay
|
|
li x20, PERIOD/20
|
|
fail_delay2:
|
|
addi x20, x20, -1
|
|
bge x20, x0, fail_delay2
|
|
|
|
# write GPO
|
|
sw x2, 0x0(x5)
|
|
|
|
j fail_loop
|
|
|
|
|