M34551E8FP 4-bit Single-Chip CMOS Microcomputer QFP-48 SMD IC
The M34551E8FP is a 4-bit single-chip CMOS microcomputer from the 4551 family, supplied in a 48-pin QFP package and intended primarily for infrared remote-control transmitter designs and related embedded control tasks. The device integrates program ROM, working RAM, multiple timers (including watchdog capability), an LCD drive/control subsystem, carrier-wave generation and a range of I/O ports — providing a compact solution where a dedicated small microcontroller with LCD and IR capability is required.
Features
- One-time PROM program memory (8192 words × 10 bits) and 280 words × 4-bit RAM.
- 4-bit CPU core compatible with the 4500 series instruction set.
- Ttypical minimum instruction execution time 3.0µs.
- On-chip clock generator supporting ceramic resonator or quartz crystal and selectable system clock division.
- Multiple timers: 8-bit timer with reload register, 14-bit timer usable as watchdog, and a 4-bit timer with reload register.
- Integrated LCD drive/control (segment & common outputs) for direct connection to small segmented LCD displays.
- Carrier-wave output and carrier frequency switching for infrared transmitter modulation.
- On-chip interrupt sources, voltage-drop detection and peripheral I/O ports (multiple 4-bit I/O ports and port D).
PINOUT
| Pin | Name | Input / Output | Function |
|---|---|---|---|
| VDD | Power supply | — | Connected to a plus power supply. |
| VSS | Ground | — | Connected to a 0 V power supply. |
| CNVSS | CNVSS | Input | Connect CNVSS to VSS and apply “L” (0 V) to CNVSS when required. |
| RESET | Reset input | I/O | N-channel open-drain I/O for system reset; internal pull-up; outputs “L” on watchdog reset or low supply detection. |
| XIN | Main clock input | Input | Main clock input for the on-chip clock generator; connect crystal/resonator between XIN and XOUT. |
| XOUT | Main clock output | Output | Main clock output; internal feedback resistor between XIN and XOUT. |
| D0–D4 | Port D outputs | Output | Each pin is a 1-bit independent output (N-channel open-drain). |
| D5 / INT | Port D / INT | I/O | 1-bit output; D5 also functions as INT input. When used as INT input set output latch = “1”. Output structure is N-channel open-drain. |
| D6 / XCIN | Port D / Sub-clock input | I/O | D6 may be used as XCIN for the sub-clock generator; otherwise normal port D function (N-channel open-drain). |
| D7 / XCOUT | Port D / Sub-clock output | Output | D7 may be used as XCOUT for the sub-clock (32.0 kHz) crystal; internal feedback resistor present. |
| P00–P03 | I/O port P0 | I/O | 4-bit I/O port, N-channel open-drain. Can act as input when output latch = “1”. Pull-up and key-on wakeup functions available. |
| P10–P13 | I/O port P1 | I/O | 4-bit I/O port, N-channel open-drain. Programmable pull-ups and wakeup functions. |
| P20/SEG16–P23/SEG19 | Input port P2 / Segment outputs | I/O | 4-bit input port; P20–P23 can also serve as LCD segment outputs SEG16–SEG19. |
| CARR | Carrier wave output | Output | Carrier-wave output for IR remote transmit; CMOS output structure. |
| SEG0–SEG15 | Segment outputs | Output | LCD segment output pins. |
| COM0–COM3 | Common outputs | Output | LCD common outputs. COM0–COM1 used for 1/2 duty; COM0–COM2 for 1/3 duty; COM0–COM3 for 1/4 duty. |
Specifications
| Parameter | Value |
|---|---|
| Device | M34551E8FP (4551 Group) |
| Program ROM | 8192 words × 10 bits (One-Time PROM variant) |
| RAM | 280 words × 4 bits |
| CPU | 4-bit 4500-series core |
| Timers | Timer1: 8-bit (reload) Timer2: 14-bit (watchdog function) Timer LC: 4-bit (reload) |
| I/O | Multiple 4-bit ports (P0–P2, Port D) and dedicated segment/common LCD outputs |
| Special Peripherals | LCD drive, carrier-wave output, carrier frequency switch, voltage-drop detection |
| Clock | External XIN/XOUT (crystal or ceramic resonator) |
| Supply Voltage | 2.5 V to 5.5 V |
| Package | 48-pin QFP (48P6S-A outline) |
Applications
- Infrared remote control transmitters and remote-control systems.
- Small appliances and consumer devices requiring segmented LCD display and simple control logic.
- Embedded controllers for simple user-interface devices where integrated timers, LCD drive and IR carrier generation are beneficial.
- Retro or maintenance replacements for designs using the 4551 family.
Package Contents
- 1× M34551E8FP 4-bit Single-Chip CMOS Microcomputer QFP-48 SMD IC.
Documents
| Datasheet | M34551E8FP |
