Notes on electronics for SKEDI (Saxophone/Keyboard? Electronic Digital Instrument).

LED eval board: ​https://www.st.com/en/ecosystems/x-nucleo-led16a1.html

• Log: SkediBuildLog
• Git: ​https://github.com/eshazen/skedi

Display ideas:

• QBASS40YG0 (1516-1020-1-ND) Brightek 14-seg 0.4" SMT common Anode (Mike bought a bunch of these)
• 160-1982-5-ND Lite-on two-digit 14 segment LED with serial interface
  • Github font: ​https://github.com/dmadison/LED-Segment-ASCII
  • NOTE: TOO BIG

Back to smaller 14-segment displays with no decoding. Decoder chip candidates:

• ATMega168 $4.50
• ATMega88 $1.63
  • Direct drive: need 1 uC per digit and maybe resistors
  • Mux drive: need fancy software
  • Shift-register drive (with blanking/disable for update). See e.g. 74LS673. Would need blanking transistor on Anode and probably series resistors on all cathodes.
• LED1642WTTR $2.50 - drives 16 LEDs, shift register, SSOP-24 (no thermal pad)
• MAX6955 - Drives up to (8) 14 seg digits. I2C interface. 36-SSOP
  • $22 each but run 4 displays

Other candidates:

• IS32FL3238 $2.35 - drives 18 LEDs, I2C, eTSSOP-28 (thermal pad)
• IS31FL3726A
• TLC5940 $3.87 - 16 output (eVOLVER PWM). 28HTSSOP (thermal pad)

Slave AVR uC ideas:

• ATTiny841: SO-14, ADCs, USART, 8k bytes flash, 512b RAM, ADCs
• ATTiny85: SO-8, ADCs, 8k bytes flash, 512 bytes RAM (ATTINY85-20SU-ND)