System Overview
Am186™CC/CH/CU Microcontrollers User’s Manual
3-17
DEBUG SUPPORT
QS1–QS0
—
O
Queue Status 1–0 values provide information to the system
concerning the interaction of the CPU and the instruction queue.
The pins have the following meanings:
The following signals are also used by emulators: A19–A0, AD15–AD0, {ADEN}, ALE, ARDY, BHE, BSIZE8, CAS1–
CAS0, CLKOUT, {CLKSEL2}–{CLKSEL1}, HLDA, HOLD, LCS, MCS3–MCS0, NMI, {ONCE}, QS1–QS0, RAS1–
RAS0, RD, RES, RESOUT, S2–S0, S6, SRDY, UCS, {UCSX8}, WHB, WLB, WR. For more information, see
Chapter 4, “Emulator Support.”
CHIP SELECTS
LCS
[RAS0]
O
Lower Memory Chip Select indicates to the system that a
memory access is in progress to the lower memory block. The
base address and size of the lower memory block are
programmable up to 512 Kbyte. LCS can be configured for 8-bit
or 16-bit bus size. LCS is three-stated with a pullup resistor
during bus-hold or reset conditions.
[MCS0]
MCS1
MCS2
[MCS3]
{UCSX8}
PIO4
[CAS1]
[CAS0]
[RAS1]
PIO5
O
Midrange Memory Chip Selects 0–3 indicate to the system
that a memory access is in progress to the corresponding region
of the midrange memory block. The base address and size of
the midrange memory block are programmable. The midrange
chip selects can be configured for 8-bit or 16-bit bus size. The
midrange chip selects are three-stated with pullup resistors
during bus-hold or reset conditions.
[MCS0] can be programmed as the chip select for the entire
middle chip select address range.
Unlike the UCS and LCS chip selects that operate relative to the
earlier timing of the nonmultiplexed A address bus, the MCS
outputs assert with the multiplexed AD address and data bus
timing.
Table 3-7
Signal Descriptions (Continued)
Signal Name
1
Multiplexed
Signal(s)
Type Description
Queue Status Pins
QS1 QS0 Queue Operation
0
0
None
0
1
First opcode byte fetched from
queue
1
0
Queue was initialized
1
1
Subsequent byte fetched from
queue
Summary of Contents for Am186 CC
Page 1: ...Am186 CC CH CU Microcontrollers User s Manual Order 21914B...
Page 4: ...iv Am186 CC CH CU Microcontrollers User s Manual...
Page 18: ...Table of Contents xviii Am186 CC CH CU Microcontrollers User s Manual...
Page 24: ...Introduction xxiv Am186 CC CH CU Microcontrollers User s Manual...
Page 40: ...Architectural Overview 1 16 Am186 CC CH CU Microcontrollers User s Manual...
Page 86: ...System Overview 3 36 Am186 CC CH CU Microcontrollers User s Manual...
Page 92: ...Emulator Support 4 6 Am186 CC CH CU Microcontrollers User s Manual...
Page 112: ...DRAM Controller 6 8 Am186 CC CH CU Microcontrollers User s Manual...
Page 134: ...Interrupts 7 22 Am186 CC CH CU Microcontrollers User s Manual...
Page 186: ...Programmable I O Signals 9 8 Am186 CC CH CU Microcontrollers User s Manual...
Page 200: ...Watchdog Timer 11 6 Am186 CC CH CU Microcontrollers User s Manual...
Page 232: ...Asynchronous Serial Ports UARTs 13 24 Am186 CC CH CU Microcontrollers User s Manual...
Page 242: ...Synchronous Serial Port SSI 14 10 Am186 CC CH CU Microcontrollers User s Manual...
Page 264: ...High Level Data Link Control HDLC 15 22 Am186 CC CH CU Microcontrollers User s Manual...
Page 332: ...Universal Serial Bus USB 18 34 Am186 CC CH CU Microcontrollers User s Manual...
Page 348: ...Register Summary A 16 Am186 CC CH CU Microcontrollers User s Manual...
Page 376: ...Index Index 18 Am186 CC CH CU Microcontrollers User s Manual...