Basic uController PCB / Circuit Design
We need a circuit / PCB designed. We will write the firmware in-house. This will be for a simple front panel control module, 9mm x 11mm, for an embedded computer system, based on an AVR 88/168/328 and a FDTI TTL UART to USB IC, powered from USB. With 5 indication LEDs wired to a 74HC595. And 11-12 buttons (NKK Switches jb15kp)(no matrix) wired directly to two 74hc165. With a LCD (mounted separately connected via ribbon cable) Kyocera NFQJ-LW-ALN wired to the uC via 4bit configuration.
We would like to be able to control dimming, both LEDs (74HC595 pin 13) and the LCD LED backlight, via a single hardware PWM pin. If reasonably possible.
The LCD would be connected via a 16pin IDC header. Also would need an ISP header and a header for USB for the internal connection to the motherboard.
Also, considering controlling ATX power/reset via this circuit. If you don't see any downfall to such a method and if we could build a circuit that would pull the PWR pin low (for the initial boot), when there is no power applied to the circuit and could block the passive, pull low behavior, when the circuit is active where the firmware could be the gatekeeper of pulling these low (to power-down/reset, etc.). Thoughts, Questions, Suggestions???