The W78E516B is an 8-bit microcontroller from Winbond that has an in-system programmable MTP-ROM for firmware updating.
The W78E516B is an 8‑bit CMOS microcontroller with up to 40 MHz operation. It provides 64 KB of main MTP‑ROM, 4 KB auxiliary MTP‑ROM, 512 bytes of on‑chip RAM, four 8‑bit I/O ports, a 4‑bit port, three 16‑bit timers and a full‑duplex serial port. Power‑management modes include idle and power‑down.
The manual describes pin configurations, functional blocks, memory organization, timer operation, clock options, power‑management settings and the in‑system programming (ISP) procedure, including register settings and example code.
| Main MTP‑ROM size | 64 KB |
|---|---|
| Auxiliary MTP‑ROM size | 4 KB |
| On‑chip RAM | 512 bytes |
| I/O ports | Four 8‑bit bi‑directional ports and one 4‑bit port (P4) |
| Timers | Three 16‑bit timer/counters |
| Serial port | Full‑duplex |
| Maximum operating frequency | 40 MHz |
Write the values 87H then 59H to the CHPENR register, then set CHPCON.0 to 1; the device will enter ISP mode after waking from idle.
The device supports an idle mode, where the CPU clock stops but peripherals run, and a power‑down mode, which stops all clocks including the oscillator.
Connect the external clock to pin XTAL1; leave XTAL2 unconnected.