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)