Renesas M32R/ECU Series User Manual page 27

1
Table 1.3.1 Description of Pin Functions (2/5)
Type Pin Name
Data bus DB0–DB15
Bus control CS0#–CS3# Chip select
RD#
WR#
BHW#/BLW# Byte high/low write
BHE#
BLE#
WAIT#
HREQ#
HACK#
Multijunction TIN0–TIN33 Timer input
timer TO0–TO44
TCLK0
–TCLK3
Signal Name Input/Output Description
Data bus Input/output This 16-bit data bus is used to connect external devices.
Output
Read Output
Write Output
Output
Byte high enable Output
Byte low enable Output
Wait Input
Hold request Input
Hold acknowledge Output
Input
Timer output Output
Timer clock Input
When writing in byte units during a write cycle, the output
data at the invalid byte position is undefined. During a
read cycle, data on the entire 16-bit bus is always read in.
However, only the data at the valid byte position is
transferred into the internal circuit.
These are chip select signals for external devices.
This signal is output when reading an external device.
This signal is output when writing to an external device.
When writing to an external device, this signal indicates the
valid byte position to which data is transferred. BHW# and
BLW# correspond to the upper address side (bits 0–7 are
valid) and the lower address side (bits 8–15 are valid),
respectively.
During an external device access, this signal indicates that
the high-order data (bits 0–7) is valid.
During an external device access, this signal indicates that
the low-order data (bits 8–15) is valid.
When accessing an external device, a low-level input on
WAIT# pin extends the wait cycle.
This input is used by an external device to request control
of the external bus. A low-level input on HREQ# pin places
the CPU in a hold state.
This signal notifies that the CPU has entered a hold state
and relinquished control of the external bus.
Input pins for the multijunction timer.
Output pins for the multijunction timer.
Clock input pins for the multijunction timer.
1-10
OVERVIEW
1.3 Pin Functions
32180 Group User's Manual (Rev.1.0)