MPC5777C EBI: 8/16 bits access to non-chip-select device

[EAlepins]

Hi,

1) In MPC5777C EBI, when communicating in non-chip-select mode with a device, WE[0:3]/BE[0:3] are not driven. Also, TSIZ[0:1] signals from previous MPC55xx/56xx family no longer exist in MPC5777C. So, how is it possible to make 8 bits or 16 bits accesses to that external device? It seems like the external device will always see 32 bits transactions...

2) Would have been helpful that RM §27.6.5 "EBI Operation with Reduced Pinout MCUs" explain how to proceed when TSIZ is not provided. "TSIZ" is mentionned as the list of pins commonly removed, but no help is provided for it. Document enhancement?

3) The MPC5777C no longer has TSIZ signals, but it is still mentioned 6 times in the Reference Manual EBI chapter. Document errata.

Thanks,

Étienne

[davidtosenovjan · Accepted solution]

Hi Etienne,

1) Cannot you use externally terminated CS access? TSIZ is not present but there is bit EBI_CAL_BRn[SETA] allowing to use externally terminated access.

2,3) Unfortunately with MPC57xx family documentation always describes generic module description with specific implantation (integration) details described at the very beginning of the section. I am not happy of that but I am afraid is it is necessary with complexity of newest devices. Section 27.3 explains all used signals of EBI module.