7160 - iCE40 Ultra/UltraLite: What are the configurable I/O pull-up resistance values for iCE40?

7160 - iCE40 Ultra/UltraLite: What are the configurable I/O pull-up resistance values for iCE40?

Description:
This article describes the 4 different configurations available for iCE40.

Solution:
There are 4 configurations for the pull up resistor of the iCE40:
- 3P3K for 3.3kohm
- 6P8K for 6.8kohm
- 10K for 10kohm
- 100k for the WEAKPULLUP

This is controlled via "PULLUP_RESISTOR" attribute, and this is supported only for iCE40UL devices.

For more information, refer to Chapter 4.1.3 of iCE40 Technology Library document (FPGA-TN-02026), available in this link: https://www.latticesemi.com/view_document?document_id=52206