Zilog Z8® CPU
The Key Z8® CPU Features Include:
General-Purpose Register File—Every RAM register acts like an accumulator, speeding instruction execution and maximizing coding efficiency. Working register groups allow fast context switching.
Flexible I/O—I/O byte, nibble, and/or bit programmable as inputs or outputs. Outputs are software programmable as open-drain or push–pull on a port basis. Inputs are Schmitt- Triggered with autolatches to hold unused inputs at a known voltage state.
Analog Inputs—Three input pins are software programmable as digital or analog inputs. When in analog mode, two comparator inputs are provided with a common reference input. These inputs are ideal for a variety of common functions, including threshold level detection, analog-to-digital conversion, and short circuit detection. Each analog input provides a unique maskable interrupt input.
Timer/Counter—The Timer/Counter (T/C) consists of a programmable 6-bit prescaler and 8-bit downcounter, with maskable interrupt upon end-of-count. Software controls T/C load/start /stop, countdown read (at any time on the fly), and maskable end-of-count interrupt. Special functions available include TIN (external counter input, external gate input, or external trigger input) and TOUT (external access to timer output or the internal system clock). These special functions allow accurate hardware input pulse measurement and output waveform generation.
Interrupts—There are six vectored interrupt sources with software-programmable enable and priority for each of the six sources.
Watchdog Timer—An internal Watchdog Timer (WDT) circuit is included as a fail-safe mechanism so that if software strays outside the bounds of normal operation, the WDT is used to time-out and reset the MCU. To maximize circuit robustness and reliability, the default WDT clock source is an internal RC circuit (isolated from the device clock source).
Auto Reset/Low-Voltage Protection—All family devices have internal Power-On Reset. ROM devices add low-voltage protection. Low-voltage protection ensures the MCU is in a known state at all times (in active RUN or RESET modes) without external hardware (or a device reset pin).
Low-EMI Operation—Mode is programmable via software or as a mask option. This new option provides for reduced radiated emission via clock and output drive circuit changes.
Low-Power—CMOS with two standby modes; STOP and HALT.
Full Z8® Instruction Set—Forty-eight basic instructions, supported by six addressing modes with the ability to operate on bits, nibbles, bytes, and words.