Here's the UB3 USB serial from the P2D2 implemented as a plug-in or solder-in module. The module is 1" x 0.57" and is meant to plug in vertically just as you see it in the pictures. As well as a standard 10-pin 0.1" header, it also has an inner 20-pin 50mil header.
I decided to use the QSOP24 pin version for some extra I/O that can also double as A/D inputs as well as other functions.
* CP2102 driver compatible (commonly included in Windows & Linux)
* Up to 8Mbd operation
* P2 reset control - holds P2 in reset until power is good.
* Smart P2 serial loader reset forces serial boot (overrides Flash/SD)
* Watchdog over I2C or I/O toggle
* Clock output to replace crystal on minimal systems
* RV-3028 RTC with 11,000uF supercap (option for 0.22F)
* 8 I/O with 220ohm resistor can drive LEDS directly or function as 12-bit A/D etc
* Baud-rate select via I2C overrides USB set baud
* 16kB I2C EEPROM emulation
* 4 LED indicators (flip-side option)
* Si5351 clock gen initialization if present
So you can even mount a uPORT onto a plug-in breadboard or operate it as an in-line module or integrated into your design.
The clock output is something that jmg has been working on and I will have to check that this hardware has the correct I/O port for that but this is something that jmg may comment on.
I decided to add an extra I2C command that writes directly to the baud-rate register so that a P2 can instruct the uPORT to use a specific baud-rate regardless of what the host side thinks it is, but I will have to test this out.
If you have a P1 design then the uPORT can replace the EEPROM (up to 16k) and also the clock too.
Can also be optioned trimmed down to an 0.8" 8-pin module without RTC loaded and also the 100mil pins can be trimmed at any time to fully access the 50mil pins.
note: the gerber viewer is having a problem with my drill file which I will resolve later. There are also a few little things left to fix up with the silkscreen etc.