Commit 5deceb84 authored by Peter Hinch's avatar Peter Hinch Committed by Damien George
Browse files

drivers, nrf24: Add nonblocking send option etc.

parent b66a31c4
"""NRF24L01 driver for Micro Python"""
"""NRF24L01 driver for Micro Python
Support for nonblocking send added. Minor fixes:
Timeout now uses pyb.elapsed_millis().
Channel numbers constrained to 125 as per datasheet.
Status register read with reg_read() - reg_read_ret_status() removed.
Default speed 250K for improved range/error rate.
"""
import pyb
......@@ -69,8 +76,10 @@ class NRF24L01:
self.pipe0_read_addr = None
pyb.delay(5)
# set address width to 5 bytes
# set address width to 5 bytes and check for device present
self.reg_write(SETUP_AW, 0b11)
if self.reg_read(SETUP_AW) != 0b11:
raise OSError("nRF24l01+ Hardware not responding")
# disable dynamic payloads
self.reg_write(DYNPD, 0)
......@@ -80,7 +89,7 @@ class NRF24L01:
self.reg_write(SETUP_RETR, (6 << 4) | 8)
# set rf power and speed
self.set_power_speed(POWER_3, SPEED_1M)
self.set_power_speed(POWER_3, SPEED_250K) # Best for point to point links
# init CRC
self.set_crc(2)
......@@ -102,13 +111,6 @@ class NRF24L01:
self.cs.high()
return buf[0]
def reg_read_ret_status(self, reg):
self.cs.low()
status = self.spi.send_recv(reg)[0]
buf = self.spi.recv(1)
self.cs.high()
return status
def reg_write(self, reg, buf):
self.cs.low()
status = self.spi.send_recv(0x20 | reg)[0]
......@@ -143,7 +145,7 @@ class NRF24L01:
self.reg_write(CONFIG, config)
def set_channel(self, channel):
self.reg_write(RF_CH, min(channel, 127))
self.reg_write(RF_CH, min(channel, 125)) # Changed from 127
# address should be a bytes object 5 bytes long
def open_tx_pipe(self, address):
......@@ -194,41 +196,55 @@ class NRF24L01:
self.spi.send(R_RX_PAYLOAD)
buf = self.spi.recv(self.payload_size)
self.cs.high()
# clear RX ready flag
self.reg_write(STATUS, RX_DR)
return buf
def send(self, buf, timeout=500):
# power up
self.reg_write(CONFIG, (self.reg_read(CONFIG) | PWR_UP) & ~PRIM_RX)
pyb.udelay(150)
# send the data
self.cs.low()
self.spi.send(W_TX_PAYLOAD)
self.spi.send(buf)
if len(buf) < self.payload_size:
self.spi.send(b'\x00' * (self.payload_size - len(buf))) # pad out data
self.cs.high()
# enable the chip so it can send the data
self.ce.high()
pyb.udelay(15) # needs to be >10us
self.ce.low()
# blocking wait for tx complete
def send(self, buf, timeout=500):
send_nonblock = self.send_nonblocking(buf)
start = pyb.millis()
while pyb.millis() - start < timeout:
status = self.reg_read_ret_status(OBSERVE_TX)
if status & (TX_DS | MAX_RT):
break
# get and clear all status flags
status = self.reg_write(STATUS, RX_DR | TX_DS | MAX_RT)
if not (status & TX_DS):
result = None
while result is None and (pyb.elapsed_millis(start) < timeout):
result = send_nonblock() # 1 == success 2 == fail
if result == 2:
raise OSError("send failed")
# power down
self.reg_write(CONFIG, self.reg_read(CONFIG) & ~PWR_UP)
def send_nonblocking(self, buf):
'''
Support for nonblocking transmission. Returns a function instance.
The first call to a function instance sends the data and returns None.
Subsequent calls test TX status returning not ready None, ready 1, error 2.
'''
init = True
def make_snb():
nonlocal init
if init:
# power up
self.reg_write(CONFIG, (self.reg_read(CONFIG) | PWR_UP) & ~PRIM_RX)
pyb.udelay(150)
# send the data
self.cs.low()
self.spi.send(W_TX_PAYLOAD)
self.spi.send(buf)
if len(buf) < self.payload_size:
self.spi.send(b'\x00' * (self.payload_size - len(buf))) # pad out data
self.cs.high()
# enable the chip so it can send the data
self.ce.high()
pyb.udelay(15) # needs to be >10us
self.ce.low()
init = False
return None # Not ready
if not (self.reg_read(STATUS) & (TX_DS | MAX_RT)):
return None # Not ready
# Either ready or failed: get and clear status flags, power down
status = self.reg_write(STATUS, RX_DR | TX_DS | MAX_RT)
self.reg_write(CONFIG, self.reg_read(CONFIG) & ~PWR_UP)
return 1 if status & TX_DS else 2
return make_snb
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