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Table 2-8
R6723-12 Pin Descriptions (continued)
Pin Name
Pin Type
External Memory Bus Interface (continued)
-WRITE
OA
-RAMSEL
OA
-ROMSEL
OA
-ES4
OA
Host Interface: The parallel interface emulates a 16S50A UART-compatible interface.
HA0-HA2
IA
HD0-HD7
IA/OB
-HCS
IA
-HRD
IA
-HWT
IA
HINT
OA
Telephone Line Interface
-RLY1 (-OH)
OA
(PE0)
-RLY3 (PE2)
OA
Pin No.
67
Write Enable. WRITE output low enables data transfer from
the D0-D7 lines to the selected device.
63
RAM Select. -RAMSEL output low selects the external
32kbyte RAM.
62
ROM Select. -ROMSEL output low selects an external 128k-
byte ROM or flash ROM.
61
ES4 Select. The -ES4 output and address line A5 are used
by external logic to generate the MDP chip select (-DPSEL =
-ES4 low and A5 low) and the DTP chip select (-SPSEL =
-ES4 low and A5 high).
83:85
Host Bus Address Lines 0-2. During a host read or write
operation with -HCS low, HA0-HA2 select an internal MCU
16550A-compatible register.
74:80,82
Host Bus Data Lines 0-7. HD0-HD7 are comprised of eight
three-state input/output lines providing bidirectional
communication between the host and the MCU Data, control
words, and status information are transferred over HD0-HD7
86
Host Bus Chip Select. -HCS input low enables MCU host
bus interface.
88
Host Bus Read. -HRD is an active low, read control input.
When -HCS is low, -HRD low allows the host to read status
information or data from a selected MCU register.
87
Host Bus Write. -HWT is an active low, write control input.
When -HCS is low, -HWT low allows the host to write data or
control words into a selected MCU register
64
Host Bus Interrupt. HINT output is set high when the
receiver error flag, received data available, transmitter
holding register empty, or modem status interrupt is asserted
HINT is reset low upon the appropriate interrupt service or
master reset operation.
59
Relay 1 Control (-OH). MCU port PE0 is assigned to the -
RLY1 output signal. The active low -RLY1 output can be used
to control the normally open off-hook relay. The -PULSE
function is also provided on this line for single -OH/-PULSE
relay application.
69
Relay 3 Control (-MUTE). When MCU port PE2 is enabled
as a relay driver, the active low -RLY3 output can be used to
control the normally open mute relay (W-class). This port
can also be used to drive the AMODE0 mux control line.
Descriptions
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