1. General Description
The AM4FBxxxx series are very low cost midi & voice synthesizers with 4-bit microprocessor. They have various features including 4-bit ALU, ROM, RAM, I/O ports, timers, clock generator, MIDI and voice synthesizer, current D/A and PWM outputs, etc. The audio synthesizer contains eight channels. Furthermore, they consist of 60 instructions in these devices. With CMOS technology, halt and standby function can minimize power dissipation. Their architectures are similar to RISC, with two stages of instruction pipeline. Most of instructions are executed in a single cycle, except for few instructions that need two or three instruction cycles.
2. Features
(1) Single power supply can operate from 2.4V to 5.5V at 8MHz.
(2) Program ROM can be up to 48k x 12-bit. (0000H~BFFFH, 1 bank)
(3) There are 3 bodies in AM4FB series:
Product Voice Duration (sec) ROM Size (12-bit)
AM4FB006B 6 24k
AM4FB010B 10 32k
AM4FB015B 15 48k
(4) Data SRAM can be up to 448 x 4-bit. (20H~FFH per page, total 2 pages)
(5) There are total 7 I/O pins, PRA and PRB[0,1,3]. Each pin of all ports can be wake-up port when they are configured as input or IO mode.
(6) There are two kinds of clock sources in the device of AM4F.
a) Resistor mode (RM).
b) High frequency crystal mode (HM).
(7) Halt and Standby Mode System clock can be totally stopped in halt mode, and cause all functions stop to save power. The Standby mode is similar to halt mode, except the system clock is still working. However, it is required to execute STB instruction to enter standby mode. Once the AM4F IC is under the standby mode and running for a period of time, the “wakeup” signal, which is generated by internal interrupt or external input change, can lead AM4F IC into the normal operating mode. Under slower system clock, that is standby mode, the power consumption is around 90uA@3V and 180uA@4.5V under the condition of 8MHz (Rosc=390Kohm). Hence, the power-saving program counter function can be applied in this mode. For details, please refer to Alpha’s Application Note number APN-05007.
