Hello everyone, I hope you are very well today, I have some doubts in which I hope you can help me, in the Sky130 documentation we can see in the management area a ROM memory, does anyone know if I can choose the information that the memory will contain?, another question, I need some crystal (oscillator) to use the PLL?, and finally, what is the maximum current that the regulator delivers?, I have been reading the documentation available and I have not found clear information to answer these questions, thanks for your help.

1. There is no ROM. Its RAM, the code is stored in external spi flash. You can program the external flash 2. I do not know. But it should work with custom trimming. The frequency/phase is not stable and may change all the time 3. There is no regulators inside the chip. They are outside. You can design custom PCB through third party and place the chips delivered on it. I do not know what regulators are placed on the prebuilt caravel breakout board

For (2), the DLL can be run in DCO mode, which is independent of any input clock, and the frequency is determined by a trim word and divider value. As Arman notes, that mode is not very stable because it is not locked to anything and is not temperature compensated. But I have used DCO mode to test the CPU up to around 40MHz (its design limit). You can also change the oscillator on the test board to any frequency up to the CPU limit of 40MHz. By default, on power-up the chip runs directly on the off-chip clock.

For (3), from the board documentation (https://github.com/efabless/caravel_board/blob/main/docs/Caravel_Board_Specs%20_clean.pdf), the regulator used is an MIC5350 https://www.microchip.com/en-us/product/MIC5350 From the schematic I see that VOUT1 (300mA) is 3.3V and VOUT2 (500mA) is 1.8V