diff --git a/hardware/interface-ascii-atmega2560/README.md b/hardware/interface-ascii-atmega2560/README.md index 2c52df6..431b479 100644 --- a/hardware/interface-ascii-atmega2560/README.md +++ b/hardware/interface-ascii-atmega2560/README.md @@ -17,9 +17,9 @@ output, supporting keyboards of up to 16 rows X 8 columns. This design uses the ## Differences from ATMega328P version - Backward compatible with the ATMega328P version, with following enhancements: -1. The Output2 can be a regualar TTL, open-collector, or open-emitter. In the +1. All the TTL outputs can be regualar push-pull TTL, open-collector, or open-emitter. In the 328P version, changing between regular TTL output and open-collector on - Output2 required changing an IC. + Output 2 required changing an IC. 1. The serial port no longer shares lines with the parallel output port, so both serial I/O and parallel output can be used at the same time without risk of conflict. However, serial I/O is not yet supported in the firmware. @@ -36,12 +36,13 @@ output, supporting keyboards of up to 16 rows X 8 columns. This design uses the be RESET, BREAK, CLEAR, etc. These may be configured as open-collector (Hi-Z for HI, GND for LO), or open-emitter (5V for high, Hi-Z for LO). - Three GPIO lines are used to control keyboard LED, or other keyboard functions. -- The DIP switch is wired into row 8 (of 0-15), to reduce RAM usage and speed up - key scanning. - A serial (UART) port is provided. This could be used to provide serial output instead or parallel output, to support a bootloader, or even to accept a serial input stream from another source to send to the host as parallel ASCII data. - +- JTAG port is provided for programming and debugging +- Two custom connectors (16-pin DIP and 1x25 0.1" header) are provided to allow + custom ASCII interfaces, or custom keyboard matrix interface. + ## Assembly Notes 1. Solder the surface-mount microcontroller first. Be sure to match pin 1 to the