[[boards:ecb:usb-fifo:start]]
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boards:ecb:usb-fifo:start [2021/04/13 09:52] – Revision from 2021-04-13 boards:ecb:usb-fifo:start [2026/06/15 12:12] (current) – external edit 127.0.0.1
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 /* Imported from Wayback Machine /* Imported from Wayback Machine
-   Original URL : https://retrobrewcomputers.org/doku.php?id=boards:ecb:usb-fifo:start +   Original URL : https://retrobrewcomputers.org/doku.php?id=boards%3Aecb%3Ausb-fifo%3Astart 
-   Snapshot date: 2021-04-13+   Snapshot date: 2026-03-08
    Generator    : wayback-archiver    Generator    : wayback-archiver
 */ */
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 The ECB-USB-FIFO board provides a high-speed interface for an EuroCard Bus machine to talk to a modern PC over USB. The board is based around the widely supported [[http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT232H.pdf|FTDI FT232H chip]] operating in “245-style asynchronous FIFO” mode. To avoid the need to solder surface-mount parts the [[https://www.adafruit.com/product/2264|Adafruit FT232H Breakout]] board is used. The ECB-USB-FIFO board provides a high-speed interface for an EuroCard Bus machine to talk to a modern PC over USB. The board is based around the widely supported [[http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT232H.pdf|FTDI FT232H chip]] operating in “245-style asynchronous FIFO” mode. To avoid the need to solder surface-mount parts the [[https://www.adafruit.com/product/2264|Adafruit FT232H Breakout]] board is used.
 +
 +On a KISS-68030 using an optimised transfer routine speeds in excess of 1MByte/sec (8Mbit/sec) can be achieved.
  
 On the PC the interface is presented as a standard USB serial interface (a “Virtual COM port” on Windows, /dev/ttyUSB* on Linux) and can be used by any application normally used with standard serial ports. Note that although it presents as a serial port, the baud rate and other serial settings configured on the Virtual COM Port are ignored, it just provides an 8-bit clean path at whatever rate you can pump data in or out of it. On the PC the interface is presented as a standard USB serial interface (a “Virtual COM port” on Windows, /dev/ttyUSB* on Linux) and can be used by any application normally used with standard serial ports. Note that although it presents as a serial port, the baud rate and other serial settings configured on the Virtual COM Port are ignored, it just provides an 8-bit clean path at whatever rate you can pump data in or out of it.
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 |(qty 2)  |16 pin DIP IC socket                                              |TE Connectivity 1-2199298-4 (Farnell order code 2445622)                                                                            | |(qty 2)  |16 pin DIP IC socket                                              |TE Connectivity 1-2199298-4 (Farnell order code 2445622)                                                                            |
 |(qty 3)  |14 pin DIP IC socket                                              |TE Connectivity 1-2199298-3 (Farnell order code 2445621)                                                                            | |(qty 3)  |14 pin DIP IC socket                                              |TE Connectivity 1-2199298-3 (Farnell order code 2445621)                                                                            |
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-\\ 
  
 ===== Notes on Construction ===== ===== Notes on Construction =====
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 It is possible to build this board with entirely 74LS series logic, and this works well. However slightly higher performance can be achieved by substituting 74AHCT parts for U6 and U9, and 74ACT for U7 and U11. Testing on a Mark IV SBC at 36.864MHz, a board using only 74LS parts requires 2 I/O wait states, whereas with the 74AHCT parts at U6 and U9 the board operates correctly with only 1 I/O wait state. U7 and U11 can use 74ACT32 which also gives a further timing improvement. The [[forum:index.php|forum thread]] has more information on how the timing improves with CMOS parts. Note that U1, U2 and U3 should always use 74LS as the bus interface benefits from having hysteresis on the inputs to improve noise rejection; the 74LS244 and 74LS245 parts have Schmitt trigger inputs. It is possible to build this board with entirely 74LS series logic, and this works well. However slightly higher performance can be achieved by substituting 74AHCT parts for U6 and U9, and 74ACT for U7 and U11. Testing on a Mark IV SBC at 36.864MHz, a board using only 74LS parts requires 2 I/O wait states, whereas with the 74AHCT parts at U6 and U9 the board operates correctly with only 1 I/O wait state. U7 and U11 can use 74ACT32 which also gives a further timing improvement. The [[forum:index.php|forum thread]] has more information on how the timing improves with CMOS parts. Note that U1, U2 and U3 should always use 74LS as the bus interface benefits from having hysteresis on the inputs to improve noise rejection; the 74LS244 and 74LS245 parts have Schmitt trigger inputs.
 +
 +FT232H boards produced after Feb 2020 (using a USB-C connector instead of Micro-USB) have two additional pins for 3V and GND at the end of the board closest to the USB connector. These should be left disconnected.
  
 ===== Photographs ===== ===== Photographs =====
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