Motorola MVME172 ユーザーズマニュアル
3-12
Computer Group Literature Center Web Site
MC2 Chip
3
General Control Register
FAST
This control bit tailors the control circuit for BBRAM to
the speed of BBRAM.
the speed of BBRAM.
When operating at 25 MHz, the FAST bit should be
cleared for devices with access times longer than 200 ns
(5 CLK cycles). The bit can be set for devices that have
access times of 200 ns or faster. It is not allowed to use
devices slower than 360 ns (9 CLK cycles), at 25 MHz.
cleared for devices with access times longer than 200 ns
(5 CLK cycles). The bit can be set for devices that have
access times of 200 ns or faster. It is not allowed to use
devices slower than 360 ns (9 CLK cycles), at 25 MHz.
When operating at 32 MHz, the FAST bit should be
cleared for devices with access times longer than 150 ns
(5 CLK cycles). The bit can be set for devices that have
access times of 150 ns or faster. It is not allowed to use
devices slower than 270 ns (9 CLK cycles), at 32 MHz.
cleared for devices with access times longer than 150 ns
(5 CLK cycles). The bit can be set for devices that have
access times of 150 ns or faster. It is not allowed to use
devices slower than 270 ns (9 CLK cycles), at 32 MHz.
MIEN
Master Interrupt Enable. When this bit is high, interrupts
from and via the MC2 chip are allowed to reach the MPU.
When it is low, all interrupts from the MC2 chip are
disabled. Also, when the bit is low, all interrupt
acknowledge cycles to the MC2 chip are passed on, via
the IACKOUT* pin. This bit is cleared by a reset.
from and via the MC2 chip are allowed to reach the MPU.
When it is low, all interrupts from the MC2 chip are
disabled. Also, when the bit is low, all interrupt
acknowledge cycles to the MC2 chip are passed on, via
the IACKOUT* pin. This bit is cleared by a reset.
PPC
PowerPC interrupt mode. When this bit is high, the
IPL<2> signal output is compatible with the int signal on
the PowerPC. When this bit is low, the IPL signal outputs
are compatible with the MC68060.
IPL<2> signal output is compatible with the int signal on
the PowerPC. When this bit is low, the IPL signal outputs
are compatible with the MC68060.
!
Caution
This bit is low for the MVME172 boards. Do not change it. If
it is changed, the board will not operate properly.
it is changed, the board will not operate properly.
ADR/SIZ
$FFF42000 (8 bits)
BIT
15
14
13
12
11
10
9
8
NAME
SCCIT1 SCCIT0
PPC
MIEN
FAST
OPER
R
R
R
R/W
R/W
R/W
R/W
R/W
RESET
0 PL
0 PL
0 PL
0 PL
0 PL
0 PL
0 PL
0 P