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Merged
Baldanos merged 3 commits into from
Dec 20, 2025
Merged

Initial support for SPI BIDIR (3-wire) #181

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ee585b3
Initial support for SPI BIDIR (3-wire)
4z0x Dec 19, 2025
7571317
Small updates
4z0x Dec 20, 2025
5dd1fa5
Small fixes
4z0x Dec 20, 2025
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1 change: 1 addition & 0 deletions src/common/mode_config.h
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Original file line number Diff line number Diff line change
Expand Up @@ -98,6 +98,7 @@ typedef struct {
uint8_t dev_polarity;
uint8_t dev_phase;
uint8_t dev_bit_lsb_msb;
uint8_t dev_bidir;
} spi_config_t;

typedef struct {
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30 changes: 26 additions & 4 deletions src/drv/stm32cube/bsp_spi.c
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Expand Up @@ -186,7 +186,12 @@ bsp_status_t bsp_spi_init(bsp_dev_spi_t dev_num, mode_config_proto_t* mode_conf)
/* SW NSS user shall call bsp_spi_select()/bsp_spi_unselect() */
hspi->Init.NSS = SPI_NSS_SOFT;
hspi->Init.BaudRatePrescaler = ((7 - mode_conf->config.spi.dev_speed) * SPI_CR1_BR_0);
hspi->Init.Direction = SPI_DIRECTION_2LINES;
/* Half-duplex / bidirectional or normal 2-line */
if(mode_conf->config.spi.dev_bidir == 0) {
hspi->Init.Direction = SPI_DIRECTION_2LINES;
} else {
hspi->Init.Direction = SPI_DIRECTION_1LINE;
}

if(mode_conf->config.spi.dev_phase == 0)
cpha = SPI_PHASE_1EDGE;
Expand Down Expand Up @@ -221,6 +226,11 @@ bsp_status_t bsp_spi_init(bsp_dev_spi_t dev_num, mode_config_proto_t* mode_conf)
/* Enable SPI peripheral */
__HAL_SPI_ENABLE(hspi);

/* Enable TX mode to avoid spurious clock output */
if(mode_conf->config.spi.dev_bidir == 1) {
SPI_1LINE_TX(hspi);
}

return status;
}

Expand Down Expand Up @@ -351,9 +361,21 @@ bsp_status_t bsp_spi_write_read_u8(bsp_dev_spi_t dev_num, uint8_t* tx_data, uint
hspi = &spi_handle[dev_num];

bsp_status_t status;
status = (bsp_status_t) HAL_SPI_TransmitReceive(hspi, tx_data, rx_data, nb_data, SPIx_TIMEOUT_MAX);
if(status != BSP_OK) {
spi_error(dev_num);
if(hspi->Init.Direction == SPI_DIRECTION_1LINE) {
status = (bsp_status_t) HAL_SPI_Transmit(hspi, tx_data, nb_data, SPIx_TIMEOUT_MAX);
if(status != BSP_OK) {
spi_error(dev_num);
return status;
}
status = (bsp_status_t) HAL_SPI_Receive(hspi, rx_data, nb_data, SPIx_TIMEOUT_MAX);
if(status != BSP_OK) {
spi_error(dev_num);
}
} else {
status = (bsp_status_t) HAL_SPI_TransmitReceive(hspi, tx_data, rx_data, nb_data, SPIx_TIMEOUT_MAX);
if(status != BSP_OK) {
spi_error(dev_num);
}
}
return status;
}
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6 changes: 5 additions & 1 deletion src/hydrabus/commands.c
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Expand Up @@ -168,6 +168,7 @@ const t_token_dict tl_dict[] = {
{ T_POKE, "poke" },
{ T_SWIO, "swio" },
{ T_CONTINUITY, "continuity" },
{ T_BIDIR, "bidir" },
/* Developer warning add new command(s) here */

/* BP-compatible commands */
Expand Down Expand Up @@ -1065,7 +1066,10 @@ t_token tokens_i2c[] = {
{ T_MSB_FIRST, \
.help = "Send/receive MSB first" }, \
{ T_LSB_FIRST, \
.help = "Send/receive LSB first" },
.help = "Send/receive LSB first" }, \
{ T_BIDIR, \
.arg_type = T_ARG_UINT, \
.help = "Bidir mode (0/1)" }, \

t_token tokens_mode_spi[] = {
{
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1 change: 1 addition & 0 deletions src/hydrabus/commands.h
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Expand Up @@ -160,6 +160,7 @@ enum {
T_POKE,
T_SWIO,
T_CONTINUITY,
T_BIDIR,
/* Developer warning add new command(s) here */

/* BP-compatible commands */
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3 changes: 3 additions & 0 deletions src/hydrabus/hydrabus_bbio_spi.c
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Expand Up @@ -302,6 +302,9 @@ void bbio_mode_spi(t_hydra_console *con)
} else {
bsp_spi_select(proto->dev_num);
}
//Set bidir mode
proto->config.spi.dev_bidir = (bbio_subcommand & 0b100)?1:0;

//Set AUX[0] (PC4) value
bbio_aux_write((bbio_subcommand & 0b10)>>1);

Expand Down
42 changes: 36 additions & 6 deletions src/hydrabus/hydrabus_mode_spi.c
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Expand Up @@ -26,10 +26,16 @@ static int exec(t_hydra_console *con, t_tokenline_parsed *p, int token_pos);
static int show(t_hydra_console *con, t_tokenline_parsed *p);

static const char* str_pins_spi1= {
"CS: PA15\r\nSCK: PB3\r\nMISO: PB4\r\nMOSI: PB5\r\n"
"CS: PA15\r\nSCK: PB3\r\n"
};
static const char* str_pins_spi2= {
"CS: PC1 (SW)\r\nSCK: PB10\r\nMISO: PC2\r\nMOSI: PC3\r\n"
"CS: PC1 (SW)\r\nSCK: PB10\r\n"
};
static const char* str_pins_spi1_io= {
"MISO: PB4\r\nMOSI: PB5\r\n"
};
static const char* str_pins_spi2_io= {
"MISO: PC2\r\nMOSI: PC3\r\n"
};
static const char* str_prompt_spi1= { "spi1" PROMPT };
static const char* str_prompt_spi2= { "spi2" PROMPT };
Expand Down Expand Up @@ -75,20 +81,22 @@ static void init_proto_default(t_hydra_console *con)
proto->config.spi.dev_polarity = 0;
proto->config.spi.dev_phase = 0;
proto->config.spi.dev_bit_lsb_msb = DEV_FIRSTBIT_MSB;
proto->config.spi.dev_bidir = 0;
}

static void show_params(t_hydra_console *con)
{
uint8_t i, cnt;
mode_config_proto_t* proto = &con->mode->proto;

cprintf(con, "Device: SPI%d\r\nGPIO resistor: %s\r\nMode: %s\r\n"
cprintf(con, "Device: SPI%d\r\nGPIO resistor: %s\r\nMode: %s\r\nBidir: %s\r\n"
"Frequency: ",
proto->dev_num + 1,
proto->config.spi.dev_gpio_pull == MODE_CONFIG_DEV_GPIO_PULLUP ? "pull-up" :
proto->config.spi.dev_gpio_pull == MODE_CONFIG_DEV_GPIO_PULLDOWN ? "pull-down" :
"floating",
proto->config.spi.dev_mode == DEV_MASTER ? "master" : "slave");
proto->config.spi.dev_mode == DEV_MASTER ? "master" : "slave",
proto->config.spi.dev_bidir == 0 ? "off" : "on");

print_freq(con, spi_speeds[proto->dev_num][proto->config.spi.dev_speed]);
cprintf(con, " (");
Expand Down Expand Up @@ -242,6 +250,17 @@ static int exec(t_hydra_console *con, t_tokenline_parsed *p, int token_pos)
return t;
}
break;
case T_BIDIR:
/* Integer parameter. */
t += 2;
memcpy(&arg_int, p->buf + p->tokens[t], sizeof(int));
if (arg_int > 1 ) {
cprintf(con, "Bidir must be 0 or 1.\r\n");
return t;
}
proto->config.spi.dev_bidir = arg_int;
bsp_spi_init(proto->dev_num, proto);
break;
default:
return t - token_pos;
}
Expand Down Expand Up @@ -357,10 +376,21 @@ static int show(t_hydra_console *con, t_tokenline_parsed *p)
tokens_used = 0;
if (p->tokens[1] == T_PINS) {
tokens_used++;
if (proto->dev_num == 0)
if (proto->dev_num == 0) {
cprint(con, str_pins_spi1, strlen(str_pins_spi1));
else
if (proto->config.spi.dev_bidir == 0) {
cprint(con, str_pins_spi1_io, strlen(str_pins_spi1_io));
} else {
cprintf(con, "IO: %s\r\n", proto->config.spi.dev_mode == DEV_MASTER ? "PB5" : "PB4");
}
} else {
cprint(con, str_pins_spi2, strlen(str_pins_spi2));
if (proto->config.spi.dev_bidir == 0) {
cprint(con, str_pins_spi2_io, strlen(str_pins_spi2_io));
} else {
cprintf(con, "IO: %s\r\n", proto->config.spi.dev_mode == DEV_MASTER ? "PC3" : "PC2");
}
}
} else {
show_params(con);
}
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1 change: 1 addition & 0 deletions src/hydrabus/hydrabus_serprog.c
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Expand Up @@ -37,6 +37,7 @@ void bbio_serprog_init_proto_default(t_hydra_console *con)
proto->config.spi.dev_polarity = 0;
proto->config.spi.dev_phase = 0;
proto->config.spi.dev_bit_lsb_msb = DEV_FIRSTBIT_MSB;
proto->config.spi.dev_bidir = 0;
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@sh7d sh7d Dec 31, 2025

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Isn't bidir intended to be enabled by default in serprog mode?
Documentation of serprog protocol states that S_SPI_MODE command (0x17), have two available modes, and the 0x00 mode that means Half Duplex is default one.
Source: https://www.flashrom.org/supported_hw/supported_prog/serprog/serprog-protocol.html, and look for S_SPI_MODE command

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@Baldanos Baldanos Jan 1, 2026

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bidir uses only one data line compared to the usual two in SPI.

The two serprog modes are for deciding whether you can write and read data at the same time (ie. the same clock cycle).
That is handled by proto->config.wwr in Hydrafw SPI mode but the serprog S_SPI_MODE is currently not handled, as I have no device to test and validate this feature. If you have some, feel free to submit a PR adding this mode ;)

}

void bbio_mode_serprog(t_hydra_console *con)
Expand Down