Visible to Intel only — GUID: shp1719424886544
Ixiasoft
Visible to Intel only — GUID: shp1719424886544
Ixiasoft
2.2.18. HPS I3C0 and I3C1 SDA/SCL pin does not comply with High-Z bus condition
Description
The I3C master circuit does not support dynamic pull-up as specified by the I3C specification. Currently, the implementation of the SCL/SDA pins driver uses HPS IO with an internal weak pull-up resistor of 20 kOhm and static 1 K pull-up is implemented on the development kit. The constant pull-up with 1 kOhm on the SDA/SCL pins prevents the dynamic switching between Open-Drain, High-Z, and Push-Pull conditions from functioning correctly for I3C, leading to non-compliance with I3C electrical specifications. This could result in various compatibility issues with I3C devices related to the following points:
- I3C0 does not support IBI
- I3C1 does not support IBI, secondary master
In this configuration of the pull-up:
- Base functionality for I3C slave and I2C slave devices were validated (dynamic and static addresses)
- I2C data rates are supported (FM, FM+)
- I3C data rates are supported up to 12.5 MHz
Workaround
No workaround for HPS IO. Alternatively, you can route the I3C to HVIO through FPGA fabric.