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ws2812/dma.py

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Python
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from machine import Pin
from rp2 import PIO, StateMachine, asm_pio
from time import sleep
import array
import uctypes
from uctypes import BF_POS, BF_LEN, UINT32, BFUINT32, struct
GPIO_BASE = 0x40014000
GPIO_CHAN_WIDTH = 0x08
GPIO_PIN_COUNT = 30
PAD_BASE = 0x4001c000
PAD_PIN_WIDTH = 0x04
ADC_BASE = 0x4004c000
PIO0_BASE = 0x50200000
PIO1_BASE = 0x50300000
DMA_BASE = 0x50000000
DMA_CHAN_WIDTH = 0x40
DMA_CHAN_COUNT = 12
DMA_SIZE_BYTE = 0x0
DMA_SIZE_HALFWORD = 0x1
DMA_SIZE_WORD = 0x2
# DMA: RP2040 datasheet 2.5.7
DMA_CTRL_TRIG_FIELDS = {
"AHB_ERROR": 31<<BF_POS | 1<<BF_LEN | BFUINT32,
"READ_ERROR": 30<<BF_POS | 1<<BF_LEN | BFUINT32,
"WRITE_ERROR": 29<<BF_POS | 1<<BF_LEN | BFUINT32,
"BUSY": 24<<BF_POS | 1<<BF_LEN | BFUINT32,
"SNIFF_EN": 23<<BF_POS | 1<<BF_LEN | BFUINT32,
"BSWAP": 22<<BF_POS | 1<<BF_LEN | BFUINT32,
"IRQ_QUIET": 21<<BF_POS | 1<<BF_LEN | BFUINT32,
"TREQ_SEL": 15<<BF_POS | 6<<BF_LEN | BFUINT32,
"CHAIN_TO": 11<<BF_POS | 4<<BF_LEN | BFUINT32,
"RING_SEL": 10<<BF_POS | 1<<BF_LEN | BFUINT32,
"RING_SIZE": 6<<BF_POS | 4<<BF_LEN | BFUINT32,
"INCR_WRITE": 5<<BF_POS | 1<<BF_LEN | BFUINT32,
"INCR_READ": 4<<BF_POS | 1<<BF_LEN | BFUINT32,
"DATA_SIZE": 2<<BF_POS | 2<<BF_LEN | BFUINT32,
"HIGH_PRIORITY":1<<BF_POS | 1<<BF_LEN | BFUINT32,
"EN": 0<<BF_POS | 1<<BF_LEN | BFUINT32
}
# Channel-specific DMA registers
DMA_CHAN_REGS = {
"READ_ADDR_REG": 0x00|UINT32,
"WRITE_ADDR_REG": 0x04|UINT32,
"TRANS_COUNT_REG": 0x08|UINT32,
"CTRL_TRIG_REG": 0x0c|UINT32,
"CTRL_TRIG": (0x0c,DMA_CTRL_TRIG_FIELDS)
}
# General DMA registers
DMA_REGS = {
"INTR": 0x400|UINT32,
"INTE0": 0x404|UINT32,
"INTF0": 0x408|UINT32,
"INTS0": 0x40c|UINT32,
"INTE1": 0x414|UINT32,
"INTF1": 0x418|UINT32,
"INTS1": 0x41c|UINT32,
"TIMER0": 0x420|UINT32,
"TIMER1": 0x424|UINT32,
"TIMER2": 0x428|UINT32,
"TIMER3": 0x42c|UINT32,
"MULTI_CHAN_TRIGGER": 0x430|UINT32,
"SNIFF_CTRL": 0x434|UINT32,
"SNIFF_DATA": 0x438|UINT32,
"FIFO_LEVELS": 0x440|UINT32,
"CHAN_ABORT": 0x444|UINT32
}
DREQ_PIO0_TX0, DREQ_PIO0_RX0, DREQ_PIO1_TX0 = 0, 4, 8
DREQ_PIO1_RX0, DREQ_SPI0_TX, DREQ_SPI0_RX = 12, 16, 17
DREQ_SPI1_TX, DREQ_SPI1_RX, DREQ_UART0_TX = 18, 19, 20
DREQ_UART0_RX, DREQ_UART1_TX, DREQ_UART1_RX = 21, 22, 23
DREQ_I2C0_TX, DREQ_I2C0_RX, DREQ_I2C1_TX = 32, 33, 34
DREQ_I2C1_RX, DREQ_ADC = 35, 36
DMA_CHANS = [struct(DMA_BASE + n*DMA_CHAN_WIDTH, DMA_CHAN_REGS) for n in range(0,DMA_CHAN_COUNT)]
DMA_DEVICE = struct(DMA_BASE, DMA_REGS)
GPIO_FUNC_SPI, GPIO_FUNC_UART, GPIO_FUNC_I2C = 1, 2, 3
GPIO_FUNC_PWM, GPIO_FUNC_SIO, GPIO_FUNC_PIO0 = 4, 5, 6
GPIO_FUNC_NULL = 0x1f
DMA_CH0_AL3_TRANS_COUNT = DMA_BASE + 0x38
class PIO_DMA_Transfer():
def __init__(self, dma_channel, sm_num, block_size, transfer_count):
self.dma_chan = DMA_CHANS[dma_channel]
self.channel_number = dma_channel
if (sm_num >= 0 and sm_num < 4):
self.dma_chan.WRITE_ADDR_REG = PIO0_BASE + 0x10 + sm_num *4
self.dma_chan.CTRL_TRIG.TREQ_SEL = sm_num
elif (sm_num < 8):
self.dma_chan.WRITE_ADDR_REG = PIO1_BASE + 0x10 + (sm_num-4) *4
self.dma_chan.CTRL_TRIG.TREQ_SEL = sm_num + 4
if (block_size == 8):
self.dma_chan.CTRL_TRIG.DATA_SIZE = DMA_SIZE_BYTE
if (block_size == 16):
self.dma_chan.CTRL_TRIG.DATA_SIZE = DMA_SIZE_HALFWORD
if (block_size == 32):
self.dma_chan.CTRL_TRIG.DATA_SIZE = DMA_SIZE_WORD
self.dma_chan.TRANS_COUNT_REG = transfer_count
#Do I just always want these?
self.dma_chan.CTRL_TRIG.INCR_WRITE = 0
self.dma_chan.CTRL_TRIG.INCR_READ = 1
def start_transfer(self, buffer):
self.dma_chan.READ_ADDR_REG = uctypes.addressof(buffer)
self.dma_chan.CTRL_TRIG.EN = 1
def transfer_count(self):
return self.dma_chan.TRANS_COUNT_REG
def busy(self):
if self.dma_chan.CTRL_TRIG.DATA_SIZE == 1:
return True
else:
return False
def abort_transfer(self):
pass
def chain_to(self, channel):
self.dma_chan.CTRL_TRIG.CHAIN_TO = channel
def get_number(self):
return self.channel_number
#looping transfers
#note -- see datasheet 2.5.7
#location of registers is -- AL3 transcount / read address trigger.
#Writing to these (from one DMA channel) will re-trigger a second DMA channel
#need to set write ring.
#could also set read ring?
#out_buff = array.array('L', ((x if (x<1000) else (2000-x)) for x in range(NSAMPLES)))
class DMA_Control_Block:
def __init__(self, this_chan, that_chan, read_address, transfer_count, loops):
self.dma_chan = DMA_CHANS[this_chan]
#note -- need to set this up to get the right location
#but for now just always control channel 0
self.dma_chan.WRITE_ADDR_REG = DMA_CH0_AL3_TRANS_COUNT
self.dma_chan.CTRL_TRIG.DATA_SIZE = DMA_SIZE_WORD
self.dma_chan.TRANS_COUNT_REG = 2 # two transfers. One is the count, one is the read_address.
#Then pauses until the other channel chains back to this.
self.buffer = array.array('L', (x for x in range(2*loops)))
for x in range(loops):
self.buffer[2*x] = transfer_count
self.buffer[2*x+1] = read_address
self.start_address = uctypes.addressof(self.buffer)
#set up read ring
that_chan.chain_to(this_chan)
self.dma_chan.CTRL_TRIG.INCR_WRITE = 1
self.dma_chan.CTRL_TRIG.INCR_READ = 1
self.dma_chan.CTRL_TRIG.RING_SEL = 1
self.dma_chan.CTRL_TRIG.RING_SIZE = 3 # 1u<<3 bytes / 8 bytes
self.dma_chan.CTRL_TRIG.TREQ_SEL = 0x3f # unpaced transfer
def start_chain(self):
self.dma_chan.READ_ADDR_REG = self.start_address
self.dma_chan.CTRL_TRIG.EN = 1
def transfer_count(self):
return self.dma_chan.TRANS_COUNT_REG
def get_read_address(self):
return self.dma_chan.READ_ADDR_REG
def busy(self):
if self.dma_chan.CTRL_TRIG.DATA_SIZE == 1:
return True
else:
return False
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