hm2_uart_setup

NAME
SYNTAX
DESCRIPTION
RETURN VALUE
SEE ALSO

NAME

hm2_uart_setup − setup a Hostmot2 UART

SYNTAX

int hm2_uart_setup(char *name, int bitrate, s32 tx_mode, s32 rx_mode){

DESCRIPTION

hm2_uart_setup Setup the bitrate for the UART named "name". "name" is a unique string given to each UART during hostmot2 setup. The names of the available UARTs are printed to standard output during the driver loading process and take the form: hm2_<board name>.<board index>.uart.<index> For example hm2_5i23.0.uart.0 The minimum bitrate is approximately 50bps, and the maximimum around the FPGA frequency, 48MHz for a 5i23. The UART function allows different RX and TX bitrates, but that is not currently supported by this driver

tx_mode is bit mask defined in the Hostmot2 regmap: Bit 0..3 = TXEnable delay. TXEnable delay specifies the transmit data
holdoff time from the TXenable signal valid state. This is used for
RS-485 (half duplex) operaton, to delay transmit data until the driver
is enabled, allowing for driver enable delays, isolation barrier delays
etc. Delay is in units of ClockLow period. Bit 4 = FIFOError, it indicates that a host push has overflowed the FIFO
(Mainly for driver debugging) Bit 5 = DriveEnableAuto, When set, enables Drive when any data is in FIFO or
Xmit Shift register,removes drive when FIFO and Xmit shift register
are empty. Bit 6 = DriveEnableBit, If DriveEnableAuto is 0, controls Drive (
for software control of Xmit drive)

tx_mode is bit mask defined in the Hostmot2 regmap: Bit 0 = FalseStart bit Status, 1 = false start bit detected Bit 1 = OverRun Status, 1 = overrun condition detected (no valid stop bit) Bit 2 = RXMaskEnable, 1= enable RXMask for half duplex operation,
0 = ignore RXMask Bit 4 = FIFOError, indicates that a host read has attemped to read more
data than available. (mainly for driver debugging) Bit 5 = LostDataError, indicates that data was received with no room in FIFO,
therefore lost Bit 6 = RXMask, RO RXMASK status Bit 7 = FIFO Has Data

rx_mode and tx_mode registers are currently write-only. There should possibly be a get-status function.

To write only to the tx_mode DriveEnable bit call this function with the bitrate unchanged and −1 as the rx_mode To change bitrate without altering mode settings send −1 to both modes.

RETURN VALUE

Returns0 on success and −1 on failure