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| author | Clifford Wolf <clifford@clifford.at> | 2017-09-17 20:38:03 +0200 |
|---|---|---|
| committer | Clifford Wolf <clifford@clifford.at> | 2017-09-18 00:43:38 +0200 |
| commit | 2cc1256ce7aab8637d82d91506cdeb73d42604b2 (patch) | |
| tree | 43333d0d771fbf695eb07f64fb0a710d07369c9f /picosoc/start.s | |
| parent | 506cda5ee65d3271c3406ecc756f85cedfbeeef6 (diff) | |
| download | picorv32-2cc1256ce7aab8637d82d91506cdeb73d42604b2.tar.gz picorv32-2cc1256ce7aab8637d82d91506cdeb73d42604b2.zip | |
Improve PicoSoC demo firmware
Diffstat (limited to 'picosoc/start.s')
| -rw-r--r-- | picosoc/start.s | 77 |
1 files changed, 33 insertions, 44 deletions
diff --git a/picosoc/start.s b/picosoc/start.s index b0c1c70..5b051b0 100644 --- a/picosoc/start.s +++ b/picosoc/start.s @@ -39,63 +39,52 @@ call main loop: j loop -.global cmd_read_spi_flash_id_worker_begin -.global cmd_read_spi_flash_id_worker_end +.global flashio_worker_begin +.global flashio_worker_end -cmd_read_spi_flash_id_worker_begin: +flashio_worker_begin: +# a0 ... data pointer +# a1 ... data length # address of SPI ctrl reg -li t0, 0x02000000 +li t0, 0x02000000 -# Manual Ctrl -li t1, 0x00 -sb t1, 3(t0) +# Set CS high, IO0 is output +li t1, 0x120 +sh t1, 0(t0) -# CS high, IO0 is output -li t1, 0x120 -sh t1, 0(t0) +# Enable Manual SPI Ctrl +li t1, 0x00 +sb t1, 3(t0) -# CS low -sb zero, 0(t0) - -# Send 0x9F (EDEC-ID Read) -li t2, 0x9F -li t3, 8 -cmd_read_spi_flash_id_worker_L1: +# SPI transfer +flashio_worker_L1: +beqz a1, flashio_worker_L3 +li t5, 8 +lbu t2, 0(a0) +flashio_worker_L2: srli t4, t2, 7 -andi t4, t4, 0x01 sb t4, 0(t0) ori t4, t4, 0x10 -slli t2, t2, 1 -addi t3, t3, -1 sb t4, 0(t0) -bnez t3, cmd_read_spi_flash_id_worker_L1 - -# Read 16 bytes and store in zero page -li t3, 0 -li a2, 16 -cmd_read_spi_flash_id_worker_L2: -li a0, 8 -li a1, 0 -cmd_read_spi_flash_id_worker_L3: -sb zero, 0(t0) -li t4, 0x10 -sb t4, 0(t0) -lb t4, 0(t0) +lbu t4, 0(t0) andi t4, t4, 2 srli t4, t4, 1 -slli a1, a1, 1 -or a1, a1, t4 -addi a0, a0, -1 -bnez a0, cmd_read_spi_flash_id_worker_L3 -sb a1, 0(t3) -addi t3, t3, 1 -bne t3, a2, cmd_read_spi_flash_id_worker_L2 +slli t2, t2, 1 +or t2, t2, t4 +andi t2, t2, 0xff +addi t5, t5, -1 +bnez t5, flashio_worker_L2 +sb t2, 0(a0) +addi a0, a0, 1 +addi a1, a1, -1 +j flashio_worker_L1 +flashio_worker_L3: -# back to MEMIO mode -li t1, 0x80 -sb t1, 3(t0) +# Back to MEMIO mode +li t1, 0x80 +sb t1, 3(t0) ret -cmd_read_spi_flash_id_worker_end: +flashio_worker_end: |