[Oberon] PO2013 - SD Image Tool
joerg.straube at iaeth.ch
Fri May 22 20:30:15 CEST 2020
The FTDI can deliver HW flow control signals RTS/CTS.
Magnus even connected them to the FPGA. Look at tge schematic.
But the Oberon system does not map them to IO registers. So, currently you don’t have access to those signals from within Oberon.
It would be a nice little task to enable CTS/RTS in Oberon. Perhaps have a try.
You have to modify the UCF
You have to modify RISC5Top.v
You have to modify the serial drivers in Oberon
> Am 22.05.2020 um 20:14 schrieb Magnus Karlsson <magnus at saanlima.com>:
> On 5/22/2020 10:32 AM, Tomas Kral wrote:
>> RS232 is RxD, TxD, and flow control signals (CTS/RTS or DSR), GND.
>> Minimum of 5 wires/signals.
>> This is failing me, unless FTDI does some magic. Can we do h/w flow
>> control over USB?
> (I guess the mailing list don't like screen capture images so here is another try)
> From FTDI web site:
> How does RTS/CTS flow control work in an FTDI chip?
> FTxxx RTS# pin is an output. It should be connected to the CTS# input pin of the device at the other end of the UART link.
> If RTS# is logic 0 it is indicating the FTxxx device can accept more data on the RXD pin.
> If RTS# is logic 1 it is indicating the FTxxx device cannot accept more data.
> RTS# changes state when the chip buffer reaches its last 32 bytes of space to allow time for the external device to stop sending data to the FTxxx device.
> FTxxx CTS# pin is an input. It should be connected to the RTS# output pin of the device at the other end of the UART link.
> If CTS# is logic 0 it is indicating the external device can accept more data, and the FTxxx will transmit on the TXD pin.
> If CTS# is logic 1 it is indicating the external device cannot accept more data. the FTxxx will stop transmitting within 0~3 characters, depending on what is in the buffer.
> Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related systems
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Oberon