1. General Description The AM4HB series is a low-cost, high performance 2-channel wavetable synthesizer with a powerful 4-bit microprocessor. There are various features including the 4-bit ALU, ROM, RAM, I/O ports, timers, interrupt, clock generator, wavetable and voice synthesizer, direct-drive outputs, etc. Watchdog timer (WDT), low voltage detector (LVDT), and infrared ray transmitter (IR) features improve system cost and reliability. Large current and open-drain outputs make their application diversified. Furthermore, with CMOS technology, the HALT and STB functions can minimize power dissipation.
The RISC MCU architecture is very easy to program and control. There are 71 instructions in these devices, and most of them are executed in only single cycle. The powerful instruction set makes users developing products easily and quickly. They are also equipped with a fine resolution Push-Pull audio output.
AM4HB is masked ROM type product chips. Some of them have their corresponding AM4HA OTP-based chips. Due to the advantage of its free of code mask, it is not only to save the mask charge, and it also reduces the lead-time greatly.
2. Features
a) 4-bit MCU with 71 instructions, which are 12-bit wide.
b) They support 8 / 16 MHz system clock, and 2 / 4 MHz high-speed instru环 芯ction cycle. Resistor mode (RM) only.
c) The program and data share the same ROM space. The maximum ROM size is up to 3Kx12-bit.
Product Notes ROM Size (12-bit)
AM4HB100A 1000 2K
AM4HB200A 2000 3K
d) There are 96 nibbles general purpose SRAM divided into 2 pages, and 48x4-bit in each page. Indirect SRAM addressing mode is supported.
e) There is an embedded 2-ch wavetable synthesizer.
f) 12-bit Push-Pull direct-drive audio output circuit is supported to provide best sound quality.
g) 7 flexible I/O pads, which are divided into 2 port groups. The ports are named from PRA[3:0] to PRB[3:1]. Two types of input and two types of output are optional for each I/O port. For input, it supports with or without a pull-high resistor and can be wake-up port. For output, it supports to normal output or open-drain configuration.
h) 11-bit SR timer for each channel can provide super fine pitch frequency resolution for 0.125us @8MHz system clock or 0.0625us @16MHz system clock.
