user manual

ON-CHIP EMULATION (OnCE) PINS
MOTOROLA ON-CHIP EMULATION (OnCE) 10 - 5
DSI/OS0 pin is an output when the processor is not in debug mode. When switching from
output to input, the pin is three-stated. During hardware reset, this pin is defined as an out-
put and it is driven low.
Note: To avoid possible glitches, an external pull-down resistor should be attached to this
pin.
CLOCK
GENERATOR
PERIPHERAL
PINS
INTERNAL
D ATA
BUS
SWITCH
PROGRAM
RAM/ROM
EXPANSION
PROGRAM
INTERRUPT
CONTROLLER
PROGRAM
DECODE
CONTROLLER
PROGRAM
ADDRESS
GENERATOR
YA B
XAB
PA B
YDB
XDB
PDB
GDB
MODC/NMI
MODB/IRQB
RESET
DATA ALU
24X24
+
56
→
56-BIT MAC
TWO 56-BIT ACCUMULATORS
EXTERNAL
ADDRESS
BUS
SWITCH
BUS
CONTROL
EXTERNAL
DATA BUS
SWITCH
ADDRESS
DATA
16 BITS
24 BITS
PORT A
MODA/IRQA
PLL
X MEMORY
RAM/ROM
EXPANSION
Y MEMORY
RAM/ROM
EXPANSION
ADDRESS
GENERATION
UNIT
OnCE
PERIPHERAL
MODULES
EXPANSION
AREA
CONTROL
24-Bit
56K Mod-
Figure 10-2 DSP56K Block Diagram
Program Control Unit