Overview
- CPU : Operable at a minimum bus cycle time of 0.5µs (microsecond)
- On-chip ROM maximum capacity : 48K bytes
- On-chip RAM capacity  :  1152 bytes   (LC866548A/40A/32A) : 896 bytes (LC866528A/24A)
- VFD automatic display controller/driver
- 16-bit timer/counter (or two 8-bit timers)
- 16-bit timer/ PWM (or two 8-bit timers)
- 8-channels ×8 bit AD Converter
- Two 8-bit synchronous serial-interface circuits (1-channel ×16 bit, 1-channel ×8 bit)
- 14-source 10-vectored interrupt system
All of the above functions are fabricated on a single chip.

FEATUREs
(1) Read Only Memory (ROM)  : LC866548A   49152 ×8 bits
                                         : LC866540A 40960 ×8 bits
                                         : LC866532A 32768 ×8 bits
                                         : LC866528A 28672 ×8 bits
                                         : LC866524A 24576 ×8 bits
(2) Random Access Memory (RAM)  :  LC866548A/40A/32A  1152 ×8 bits
                                                  LC866528A/24A 896 ×8 bits
(3) Bus Cycle Time / Instruction Cycle Time
    The bus cycle time indicates the speed to read ROM.
(4) Ports
- Input/output ports  : 3 ports  (16 terminals : port 1, 7, 8)
Input/output port programmable in a bit
- 15V withstand Input/output ports  : 2 ports  (16 terminals)
Input/output port programmable nibble unit  : 1 port  (8 terminals : port 0)
(When the N-channel open drain output is selected, the data in a bit can be inputted.)
Input/output port programmable in a bit  : 1 port  (8 terminals : port 3)
- Input port  : 2 ports  (6 terminals : port 7, 8)
- VFD output port  : 52 terminals
Large current output for digit  : 16 terminals
Pull-down resistor option available
- Other function
Input/output port  : 2 ports  (12 terminals : port F, G)
Input port  : 3 ports  (24 terminals : port C, D, E)
(5) VFD automatic display controller
- Segment/digit output pattern programmable
Any segment/digit combination available
VFD parallel-drive available
- 16-step dimmer function available
(6) AD converter
- 8-channels ×8-bit AD converter
(7) Serial interface
- 1-channel ×16-bit serial interface circuits
- 1-channel ×8-bit serial interface circuits
- LSB first/MSB first function available
- Internal 8-bit baud-rate generator in common with two serial interface circuits
- SIO automatic transmission available (2-32 byte data can be transmitted with program automatically and
continuously.) LC866548/40/32/28/24A
(8) Timers
- Timer 0 : 16-bit timer/counter with 2-bit prescaler + 8-bit programmable prescaler
Mode 0 :   Two 8-bit timers with programmable prescaler
Mode 1 :   8-bit timer with a programmable prescaler + 8-bit counter
Mode 2 :   16-bit timer with a programmable prescaler
Mode 3 : 16-bit counter
The resolution of Timer is tCYC. (tCYC : cycle time)
- Timer 1 : 16-bit timer/PWM with
Mode 0 : Two 8-bit timers
Mode 1 :   8-bit timer + 8-bit PWM
Mode 2 : 16-bit timer
Mode 3 :   Variable-bit PWM (9-16 bits)
In Mode 0 and Mode 1, the resolution of Timer and PWM is tCYC.
In Mode 2 and Mode 3, the resolution of Timer and PWM selectable : tCYCor 1/2tCYC by program
- Base timer
Every 500ms overflow system for a clock application (using 32.768kHz crystal oscillation for Base timer
clock) Every 976µs, 3.9ms, 15.6ms, 62.5ms overflow system (using 32.768kHz crystal oscillation for Base timer
clock) The Base timer clock selectable ; 32.768kHz crystal oscillation, System clock, and programmable prescaler
output of Timer 0
(9) Buzzer output
- The Buzzer sound frequency selectable ; 4kHz, 2kHz (using 32.768kHz crystal oscillation for Base timer clock)
(10) Remote control receiver circuit (connected to the P73/INT3/T0IN terminal)
- Noise rejection function (the time constant of noise rejection filter : 1tCYC/16tCYC/64tCYC) (tCYC : instruction cycle time)
- Polarity switching
(11) Watchdog timer
- The watchdog timer is taken on RC outside
- Watchdog timer operation selectable : interrupt system, system reset
(12) Interrupt system
- 14-source 10-vectored interrupts :
1. External Interrupt INT0 (include watchdog timer)
2. External Interrupt INT1
3. External Interrupt INT2, Timer/counter T0L (Lower 8 bits)
4. External Interrupt INT3, base timer
5. Timer/counter T0H (Upper 8 bits)
6. Timer T1H / T1L
7. Serial interface SIO0
8. Serial interface SIO1
9. AD converter
10. VFD automatic display controller, Port 0
- Built-in Interrupt priority control register Microcontroller allows 3 levels of interrupt ; low level, high level, and highest level of multiplex interrupt. It can specify a low level or a high level interrupt priority from INT2/T0L through port 0 (i. e. the above interrupt number from three through ten). It can also specify a low level or the highest level interrupt priority to INT0 and INT1.
(13) Subroutine stack levels
- 128 levels (Max.) : Stack area included in RAM area