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Semiconductor Group
103
On-Chip Peripheral Components
Table 7-10
Status of External Pins During Idle and Power-Down Mode
The watchdog timer is the only peripheral which is automatically stopped during idle. The idle mode
makes it possible to "freeze" the processor’s status for a certain time or until an external event
causes the controller to go back into normal operating mode. Since the watchdog timer is stopped
during idle mode, this useful feature of the SAB 80C515/80C535 is provided even if the watchdog
function is used simultaneously.
lf the idle mode is to be used the pin PE must be held low. Entering the idle mode is to be done by
two consecutive instructions immediately following each other. The first instruction has to set the
flag bit IDLE (PCON.0) and must not set bit IDLS (PCON.5), the following instruction has to set the
start bit IDLS (PCON.5) and must not set bit IDLE (PCON.0). The hardware ensures that a
concurrent setting of both bits, IDLE and IDLS will not initiate the idle mode. Bits IDLE and IDLS will
automatically be cleared after having been set. lt one of these register bits is read the value shown
is zero (0). Figure 7-44 shows special function register PCON. This double-instruction sequence is
implemented to minimize the chance of unintentionally entering the idle mode.
Note that PCON is not a bit-addressable register, so the above mentioned sequence for entering
the idle mode is to be done by byte handling instructions.
Outputs
Last Instruction Executed from
Internal Code Memory
Last Instruction Executed from
External Code Memory
Idle
Power-down
Idle
Power-down
ALE
High
Low
High
Low
PSEN
High
Low
High
Low
Port 0
Data
Data
Float
Float
Port 1
Data/alternate
outputs
Data/
last output
Data/alternate
outputs
Data/
last output
Port 2
Data
Data
Address
Data
Port 3
Data/alternate
outputs
Data/
last output
Data/alternate
outputs
Data/
last output
Port 4
Data
Data
Data
Data
Port 5
Data
Data
Data
Data
*
Summary of Contents for SAB 80515 Series
Page 9: ...Semiconductor Group 9 Introduction Figure 1 2 Block Diagram ...
Page 12: ...Semiconductor Group 12 Fundamental Structure Figure 2 1 Detailed Block Diagram ...
Page 18: ...Semiconductor Group 18 Central Processing Unit Figure 3 1 Fetch Execute Sequence ...
Page 73: ...Semiconductor Group 73 On Chip Peripheral Components Figure 7 25 A D Converter Block Diagram ...
Page 83: ...Semiconductor Group 83 On Chip Peripheral Components Figure 7 33 a Timer 2 Block Diagram ...
Page 215: ...Device Specifications Semiconductor Group 215 ...
Page 217: ...Device Specifications Semiconductor Group 217 Pin Configuration P LCC 68 ...
Page 219: ...Device Specifications Semiconductor Group 219 Logic Symbol ...
Page 226: ...Device Specifications Semiconductor Group 226 Figure 1 Block Diagram ...
Page 229: ...Device Specifications Semiconductor Group 229 Figure 2 Memory Address Spaces ...
Page 239: ...Device Specifications Semiconductor Group 239 Figure 4 Block Diagram of the A D Converter ...
Page 241: ...Device Specifications Semiconductor Group 241 Figure 5 Interrupt Request Sources ...
Page 242: ...Device Specifications Semiconductor Group 242 Figure 6 Interrupt Priority Level Structure ...