The ERO 3.4 upgrades were completed in June, 2008.
- The Exar 4-channel UART on the 'S12 expansion board never worked quite right. Some strange ESD (?) problem caused it to frequently just stop responding. Even basic GPIO functions stopped working.
- Still having speed controller problems...
- The Victor 884's extremely non-linear response caused heartaches with my PID controller
- The Sabertooth 2x10RC had quirky firmware bugs, including intermittently not responding at all
- Upgraded processor again! This time with [Freescale] MC9S12XDP512 (S12X). It has 6 serial ports, vs. 3 on the 'S12E128, so there is only a net loss of 1 serial port from the external UART design.
- Replaced 'S12 expansion board
with
S12X interface board.
Much cleaner design because:
- Bus expansion no longer required
- CPU sits right on top (like daughter card) instead of being connected by ribbon cables
- Double-sided Printed Circuit Board instead of wire-wrap
- Replaced Electronic Speed Controller (ESC) again! This time with Sabertooth 2x25 from Dimension Engineering. This one meets all my requirements, but only if I use the serial interface to control it. So now I'm down another serial port (in case you haven't noticed yet, I consider serial ports Golden for future expansion).
- The new S12X processor is twice as fast as the S12 and has a dedicated peripheral co-processor called "XGATE" which can offload much of the I/O overhead from the main CPU
