In the response to the request for what's different between the older version of Caravel (used on MPW-2 to MPW-5, and ChipIgnite through 2110C inclusive), here's a summary: • Old Caravel: Has hold violations between the GPIO configuration blocks and requires running a calibration script to determine where the violations are and compensate the configuration accordingly. Some configurations may not be possible, in which case an alternative configuration like a weak pull-up or weak pull-down state may be necessary. The calibration requires detecting values at the pins which cannot be done simultaneously with setting the value at the pin due to the 1-wire communication to each GPIO, so the Nucleo board has been added to the development board system mainly for the purpose of running one side of the calibration. When running a program, you need to include the configuration vectors produced by the calibration and run a subroutine that bit-bangs the configuration to the GPIOs. • New Caravel: No hold violations. When running a program, you just need to specify the configuration for each GPIO and then trigger the serial transfer. • Old Caravel: One-wire communication from the management SoC to each GPIO. Each GPIO can be configured for use by the management SoC as an input or an output, but not both at the same time. The managment SoC can monitor user project output or provide stimulus to the user project, but the setup is rather complicated. • New Caravel: Two-wire communication from the management SoC to each GPIO. Each GPIO can be configured to read and write simultaneously, which makes it easy to set up modes where the management SoC monitors the user project output or provides stimulus to the user project. • Old Caravel: An error in the memory map prevents many housekeeping functions from being accessed from the management SoC. • New Caravel: The entire memory map is accessible from both the management SoC and the housekeeping SPI, including all housekeeping registers. • Old Caravel: The housekeeping SPI had hold violations and certain housekeeping register bits could not be set. For example, the DLL can be turned on in DCO (free-running) mode, but not in DLL (locked) mode. • New Caravel: All housekeeping SPI registers are fully accessible and the DLL has been completely tested and verified. If I think of more items, I'll add to this list.