Espressif has moved the SDK to GitHub. At this point, It is version 2.1. I have no indication that they have done anything with the ADC Feature I requested. I have not updated to this newest SDK yet. I will do that before I spend any time working on firmware.
New component costing:
The 74LVC2T45 level shifter chips are US $0.32 each in low quantities. The PCA9306 I2C level shifter are about US $0.60 each in low quantities. This results in the costs of the level shift components arount $1.50. The original single part costs around US $1.25 each in low quantities. This is not a big difference in cost but it does affect board space.
I have updated this website to default to TLS for connections. I have a certificate supplied by my hosting provider. I have also turned on member accounts. I am hoping this will make it more convenient you, the readers to join the conversation.
Voltage level shifter:
I am still trying to decide the best way to go for adjusting to the target platform voltage. SPI typically needs 3 bits output (SS, SCLK, MOSI) and one bit input(MISO) Sometimes SPI needs more. JTAG needs 4 pins output(TCK, TMS, TDO, TRST) and one bit input(TDI). I found the JTAG signal description on this page. I2C needs two bits of bi-directional open drain signals. I don’t know of any MicroControllers that can be programmed over I2C but there are flash memories that are programmed that way.
Based on this information, I can see that I would want 4 bits of output and 2 input along with a 2 bit open drain bi-directional. This gives me a total of eight bits of data available to connect to the target device. In addition to that, I need Target Vcc and GND and Vpp. Continue reading