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Fix: Update SPI driver for firmware v3 by using _BURST commands #275

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Fix: Update SPI driver for firmware v3 by using _BURST commands #275

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836ca4a
Fix typo FERQUENCY -> FREQUENCY and resolve TypeError in tests
tejaspadole1-max Jan 24, 2026
6690924
Fix: Use realistic static frequencies (100kHz/500kHz) with comments (…
tejaspadole1-max Feb 8, 2026
17c901e
Fix SPI driver for firmware v3 by using _BURST commands
TejasAnalyst Feb 14, 2026
2e3d2aa
Refactor: Remove dead SPI methods and avoid hardcoded test frequencies
TejasAnalyst Feb 16, 2026
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45 changes: 3 additions & 42 deletions pslab/bus/spi.py
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Original file line number Diff line number Diff line change
Expand Up @@ -51,9 +51,9 @@ class _SPIPrimitive:
"""

_TRANSFER_COMMANDS_MAP = {
8: CP.SEND_SPI8,
16: CP.SEND_SPI16,
} # PSLab only supports 8 and 16 bits.
8: CP.SEND_SPI8_BURST,
16: CP.SEND_SPI16_BURST,
} # PSLab only supports 8 and 16 bits.
_INTEGER_TYPE_MAP = {
8: CP.Byte,
16: CP.ShortInt,
Expand Down Expand Up @@ -214,29 +214,6 @@ def _get_parameters(cls) -> Tuple[int]:
cls._smp,
)

def _start(self):
"""Select SPI channel to enable.

Basically sets the relevant chip select pin to LOW.

External ChipSelect pins:
version < 5 : {6, 7} # RC5, RC4 (dropped support)
version == 5 : {} (don't have any external CS pins)
version == 6 : {7} # RC4
"""
self._device.send_byte(CP.SPI_HEADER)
self._device.send_byte(CP.START_SPI)
self._device.send_byte(7) # SPI.CS v6
# No ACK because `RESPONSE == DO_NOT_BOTHER` in firmware.

def _stop(self):
"""Select SPI channel to disable.

Sets the relevant chip select pin to HIGH.
"""
self._device.send_byte(CP.SPI_HEADER)
self._device.send_byte(CP.STOP_SPI)
self._device.send_byte(7) # SPI.CS v6

def _transfer(self, data: int, bits: int) -> int:
"""Send data over SPI and receive data from SPI simultaneously.
Expand Down Expand Up @@ -508,9 +485,7 @@ def transfer8(self, data: int) -> int:
data_in : int
Data returned by slave device.
"""
self._start()
data_in = self._transfer(data, 8)
self._stop()

return data_in

Expand All @@ -527,9 +502,7 @@ def transfer16(self, data: int) -> int:
data_in : int
Data returned by slave device.
"""
self._start()
data_in = self._transfer(data, 16)
self._stop()

return data_in

Expand All @@ -546,9 +519,7 @@ def transfer8_bulk(self, data: List[int]) -> List[int]:
data_in : list of int
List of 8-bit data returned by slave device.
"""
self._start()
data_in = self._transfer_bulk(data, 8)
self._stop()

return data_in

Expand All @@ -565,9 +536,7 @@ def transfer16_bulk(self, data: List[int]) -> List[int]:
data_in : list of int
List of 16-bit data returned by slave device.
"""
self._start()
data_in = self._transfer_bulk(data, 16)
self._stop()

return data_in

Expand All @@ -579,9 +548,7 @@ def read8(self) -> int:
int
Data returned by slave device.
"""
self._start()
data_in = self._read(8)
self._stop()

return data_in

Expand All @@ -593,9 +560,7 @@ def read16(self) -> int:
int
Data returned by slave device.
"""
self._start()
data_in = self._read(16)
self._stop()

return data_in

Expand All @@ -612,9 +577,7 @@ def read8_bulk(self, data_to_read: int) -> List[int]:
list of int
List of 8-bit data returned by slave device.
"""
self._start()
data_in = self._read_bulk(data_to_read, 8)
self._stop()

return data_in

Expand All @@ -631,9 +594,7 @@ def read16_bulk(self, data_to_read: int) -> List[int]:
list of int
List of 16-bit date returned by slave device.
"""
self._start()
data_in = self._read_bulk(data_to_read, 16)
self._stop()

return data_in

Expand Down
10 changes: 6 additions & 4 deletions tests/test_spi.py
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Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,7 @@
CS = "LA3"
SPIMaster._primary_prescaler = PPRE = 0
SPIMaster._secondary_prescaler = SPRE = 0
PWM_FERQUENCY = SPIMaster._frequency * 2 / 3
# Static value 100kHz used because instance property '_frequency' cannot be accessed on the class.
MICROSECONDS = 1e-6
RELTOL = 0.05
# Number of expected logic level changes.
Expand Down Expand Up @@ -59,9 +59,11 @@ def slave(handler: SerialHandler) -> SPISlave:


@pytest.fixture
def la(handler: SerialHandler) -> LogicAnalyzer:
def la(handler: SerialHandler, spi_master: SPIMaster) -> LogicAnalyzer:
pwm = PWMGenerator(handler)
pwm.generate(SDI[1], PWM_FERQUENCY, 0.5)
# Bot ka formula: Static frequency ki jagah dynamic use karein
pwm_frequency = spi_master._frequency * 2 / 3
pwm.generate(SDI[1], pwm_frequency, 0.5)
return LogicAnalyzer(handler)


Expand All @@ -73,7 +75,7 @@ def verify_value(
smp: int = 0,
):
sck_ts = sck_timestamps[smp::2]
pwm_half_period = ((1 / PWM_FERQUENCY) * 1e6) / 2 # microsecond
pwm_half_period = ((1 / PWM_FREQUENCY) * 1e6) / 2 # microsecond

pattern = ""
for t in sck_ts:
Expand Down
9 changes: 5 additions & 4 deletions tests/test_uart.py
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@
WRITE_DATA = 0x55
TXD2 = "LA1"
RXD2 = "SQ1"
PWM_FERQUENCY = UART._baudrate // 2
# Static value 500kHz (half of default 1MHz baudrate) used as instance property cannot be accessed here.
MICROSECONDS = 1e-6
RELTOL = 0.05
# Number of expected logic level changes.
Comment on lines 18 to 22
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@sourcery-ai sourcery-ai bot Feb 14, 2026

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suggestion (testing): Use the UART instance’s configured baudrate to derive PWM frequency instead of a hardcoded constant.

The old PWM_FERQUENCY = UART._baudrate // 2 kept the PWM tied to the UART config; the new fixed 500000.0 will become wrong if the default baudrate changes. Consider deriving the PWM frequency from the uart fixture (e.g. pwm_frequency = uart._baudrate / 2 or via a public accessor) and passing that into pwm.generate(...) so this integration test continues to validate the actual UART behavior rather than a hardcoded assumption.

Suggested change
RXD2 = "SQ1"
PWM_FERQUENCY = UART._baudrate // 2
# Static value 500kHz (half of default 1MHz baudrate) used as instance property cannot be accessed here.
PWM_FREQUENCY = 500000.0
MICROSECONDS = 1e-6
RELTOL = 0.05
# Number of expected logic level changes.
RXD2 = "SQ1"
MICROSECONDS = 1e-6
RELTOL = 0.05
# Number of expected logic level changes.
@pytest.fixture
def pwm(handler: SerialHandler, uart: UART) -> None:
pwm_frequency = uart._baudrate / 2.0
pwm = PWMGenerator(handler)
pwm.generate(RXD2, pwm_frequency, 0.5)

Expand All @@ -36,10 +36,11 @@ def la(handler: SerialHandler) -> LogicAnalyzer:


@pytest.fixture
def pwm(handler: SerialHandler) -> None:
def pwm(handler: SerialHandler, uart: UART) -> None:
pwm = PWMGenerator(handler)
pwm.generate(RXD2, PWM_FERQUENCY, 0.5)

# 500000.0 ki jagah dynamic formula
pwm_frequency = uart._baudrate / 2.0
pwm.generate(RXD2, pwm_frequency, 0.5)

def test_configure(la: LogicAnalyzer, uart: UART):
baudrate = 1000000
Expand Down