I've made a custom board with an AT90CAN128, and I can't get my USBTinyISP to connect to it. I've verified the programmer is good, as it connects to a 328p and a AT90CAN128 on a dev board fine.

I made a second board now with a spare IC, and only soldered the IC, an ICSP connector, and a 10k pullup resistor for RESET. I can not get that one to connect either. My board does have a 16MHz crystal, while the second board does not.

I can find no solder bridges or mistakes so far on my board. I bought this exact IC from Digi-Key. I thought all Atmel AVRs were shipped with ICSP fuses enabled. Am I missing something, or am I going to need a high voltage programmer?

Current consumption is 40mA, that includes the power LED, a 3v3 regulator, and a MCP2561.

Bare Board Schematic Entire Schematic Microscope Image Board showing orientation

  • \$\begingroup\$ Probe the and ground pins, also visually verify their connectivity in the PCB design or on an unpopulated spare. You do have bypass caps somewhere, right? Is the power consumption reasonable? Are your sure the chip is mounted in the correct orientation? \$\endgroup\$ May 6 '19 at 4:39
  • \$\begingroup\$ I have verified 5v/GND on both VCC and GND pins (top and bottom). I believe I have the orientation correctly, there were two identations at opposite ends that could be seen as indexing corners, so I went with keeping the text upright. I'm at a loss and am now thinking I may need an HV programmer, something I don't have access to \$\endgroup\$
    – Jeff
    May 6 '19 at 16:49
  • \$\begingroup\$ Perhaps you could post a picture of your PCB, the location of the crystal and its capacitors is fairly critical. Also, the default fuse info is all available on-line. \$\endgroup\$
    – Wendall
    May 6 '19 at 16:53
  • \$\begingroup\$ I've editted the above post \$\endgroup\$
    – Jeff
    May 6 '19 at 16:54
  • \$\begingroup\$ Correct. I've yet to even set fuses on my first board, so I assume it should still be set to the internal oscillator \$\endgroup\$
    – Jeff
    May 6 '19 at 17:06

I've found out I routed the ICSP connector wrong. MISO/MOSI are not used like other Atmel AVRs, they instead use pins 2/3 (PE0,PE1)


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