Z86E7216PSC View Datasheet(PDF) - Zilog
Part Name
Description
MFG CO.
'Z86E7216PSC' PDF : 74 Pages View PDF
Z86E72/E73
OTP IR Microcontrollers
PIN FUNCTIONS
/DS (Output, active Low). Data Strobe is activated once for Port 0 (P07-P00). Port 0 is an 8-bit, bidirectional, CMOS
1 each external memory transfer. For a READ operation, compatible port. These eight I/O lines are configured un-
data must be available prior to the trailing edge of /DS. For der software control as a nibble I/O port, or as an address
WRITE operations, the falling edge of /DS indicates that port for interfacing external memory. The output drivers
output data is valid.
are push-pull. Port 0 is placed under handshake control. In
this configuration, Port 3, lines P32 and P35 are used as
/AS (Output, active Low). Address Strobe is pulsed once the handshake control /DAV0 and RDY0. Handshake sig-
at the beginning of each machine cycle. Address output is nal direction is dictated by the I/O direction to Port 0 of the
through Port 0/Port 1 for all external programs. Memory upper nibble P07-P04. The lower nibble must have the
address transfers are valid at the trailing edge of /AS. Un- same direction as the upper nibble.
der program control, /AS is placed in the high-impedance
state along with Ports 0 and 1, Data Strobe, and For external memory references, Port 0 can provide ad-
Read/Write.
dress bits A11-A8 (lower nibble) or A15-A8 (lower and up-
per nibble) depending on the required address space. If
XTAL1 Crystal 1 (time-based input). This pin connects a the address range requires 12 bits or less, the upper nibble
parallel-resonant crystal, ceramic resonator, LC, or RC of Port 0 can be programmed independently as I/O while
network or an external single-phase clock to the on-chip the lower nibble is used for addressing. If one or both nib-
oscillator input.
bles are needed for I/O operation, they must be configured
XTAL2 Crystal 2 (time-based output). This pin connects a
parallel-resonant, crystal, ceramic resonant, LC, or RC
by writing to the Port 0 mode register. After a hardware re-
set, Port 0 is configured as an input port.
network to the on-chip oscillator output.
Port 0 is set in the high-impedance mode if selected as an
R//W Read/Write (output, write Low). The R//W signal is
Low when the CCP is writing to the external program or
address output state along with Port 1 and the control sig-
nals /AS, /DS, and R//W (Figure 8).
data memory.
R//RL (input). This pin, when connected to GND, disables
the internal ROM and forces the device to function as a
A software option is available to program 0.4 VDD CMOS
trip inputs on P00-P03. This allows direct interface to
mouse/trackball IR sensors.
ROMless Z8. (Note that, when left unconnected or pulled An optional 200 kOhm pull-up is available as a software
high to VCC, the part functions normally as a Z8 ROM ver- option of all Port 0 bits with nibble select.
sion.)
These pull-ups are disabled when configured (bit by bit) as
an output.
DS96LVO1100
PRELIMINARY
1-19
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