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Device Specifications
Semiconductor Group
224
PSEN
49
47
O
The Program store enable
output is a control signal that enables the
external program memory to the bus
during external fetch operations. It is
activated every six oscillator periods,
except during external data memory
accesses. The signal remains high during
internal program execution.
ALE
50
48
O
The Address latch enable
output is used for latching the address into
external memory during normal operation.
It is activated every six oscillator periods,
except during an external data memory
access.
EA
51
49
I
External access enable
When held high, the SAB 80C515
executes instructions from the internal
ROM as long as the PC is less than 8192.
When held low, the SAB 80C515 fetches
all instructions from external program
memory. For the SAB 80C535 this pin
must be tied low.
P0.0-P0.7 52-59
52-59
I/O
Port 0
is an 8-bit open-drain bidirectional I/O
port.
Port 0 pins that have 1’s written to them
float, and in that state can be used as
high-impedance inputs.
Port 0 is also the multiplexed low-order
address and data bus during accesses to
external program and data memory. In
this application it uses strong internal
pullup resistors when issuing 1’s.
Port 0 also outputs the code bytes during
program verification in the SAB 80C515.
External pullup resistors are required
during program verification.
Pin Definitions and Functions (cont’d)
Symbol
Pin
P-LCC-68
Pin
P-MQFP-80
Input (I)
Output (O)
Function
*
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 ...