TMP91C824
91C824-86
(6) Procedure for setting chip select/wait control
When using the chip select/wait control function, set the registers in the following order:
!
Set the Memory Start Address Registers MSAR0 to MSAR3.
Set the start addresses for CS0 to CS3.
"
Set the Memory Address Mask Registers MAMR0 to MAMR3.
Set the sizes of CS0 to CS3.
#
Set the chip select/wait control registers B0CS to B3CS.
Set the Chip Select output waveform, data bus width, number of waits and Master
Enable/Disable status for /CS0 to /CS3.
The CS0 to S3 pins can also function as pins P60 to P63. To output a Chip Select signal
using one of these pins, set the corresponding bit in the Port 6 Function Register P6FC to “1”.
If a CS0 “to S3 address is specified which is actually an internal I/O and RAM area address,
the CPU accesses the internal address area and no Chip Select signal is output on any of the
/CS0 to /CS3 pins.
Setting example:
In this example CS0 is set to be the 64-Kbyte area 010000H to 01FFFFH. The bus width is set to 16 bits
and the number of waits is set to 0.
MSAR0
=
01H............... Start address: 010000H
MAMR0
=
07H ............. Address area: 64 Kbytes
B0CS
=
83H................... ROM/SRAM, 16-bit data bus, zero waits, CS0 area settings enabled