z86e72 ZiLOG Semiconductor, z86e72 Datasheet - Page 29

• Manufacturer Part Number: z86e72
• Description: Otp Microcontroller
• Manufacturer: ZiLOG Semiconductor

Pin Functions
PS008704-0507
/DS (Output, Active Low)
/AS (Output, Active Low)
XTAL1 Crystal 1 (Time-Based Input)
XTAL2 Crystal 2 (Time-Based Output)
R//W Read/Write (Output, Write Low)
R//RL (Input)
Port 0 (P07–P00)
Note:
Data Strobe is activated once for each external memory transfer. For a READ
operation, data must be available before the trailing edge of /DS. For WRITE
operations, the falling edge of /DS indicates that output data is valid.
Address Strobe is pulsed once at the beginning of each machine cycle. Address
output is through Port 0/Port 1 for all external programs. Memory address trans-
fers are valid at the trailing edge of /AS. Under program control, /AS is placed in
the high-impedance state along with Ports 0 and 1, Data Strobe, and Read/Write.
This pin connects a parallel-resonant crystal, ceramic resonator, LC, or RC net-
work or an external single-phase clock to the on-chip oscillator input.
This pin connects a parallel-resonant, crystal, ceramic resonant, LC, or RC net-
work to the on-chip oscillator output.
The R//W signal is Low when the CCP is writing to the external program or data
memory.
This pin, when connected to GND, disables the internal ROM and forces the
device to function as a ROMless Z8.
Port 0 is an 8-bit, bidirectional, CMOS-compatible port. These eight I/O lines are
configured under software control as a nibble I/O port or as an address port for
interfacing external memory. The output drivers are push-pull. Port 0 is placed
under handshake control. In this configuration, Port 3, lines P32 and P35 are
used as the handshake control /DAV0 and RDY0. Handshake signal direction is
When left unconnected or pulled high to V
normally as a Z8 ROM version.
CC
, the part functions
OTP Microcontroller
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