|
|
|
|
|
|
|
|
|
|
|
| 80C186EA/80C188EA, 80L186EA/80L188EA | ||||
|
|
|
|
|
|
|
|
|
|
| Table 3. Pin Descriptions (Continued) | |||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Pin | Pin | Input | Output | Description | |||||||||||
| Name | Type | Type | States | ||||||||||||
|
|
|
|
|
| |||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
WR/QS1 | O |
| H(Z) | WRite output signals that data available on the data bus are to be | ||||||||||||
|
|
|
|
|
|
|
|
|
|
| R(Z) | written into the accessed memory or I/O device. In Queue Status | ||||
|
|
|
|
|
|
|
|
|
|
| P(1) | Mode, QS1 provides queue status information along with QS0. | ||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| ||
ARDY | I | A(L) |
| Asychronous ReaDY is an input to signal for the end of a bus cycle. | ||||||||||||
|
|
|
|
|
|
|
|
|
| S(L) |
| ARDY is asynchronous on rising CLKOUT and synchronous on falling | ||||
|
|
|
|
|
|
|
|
|
|
|
| CLKOUT. ARDY or SRDY must be active to terminate any processor | ||||
|
|
|
|
|
|
|
|
|
|
|
| bus cycle, unless they are ignored due to correct programming of the | ||||
|
|
|
|
|
|
|
|
|
|
|
| Chip Select Unit. | ||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| ||
SRDY | I | S(L) |
| Synchronous ReaDY is an input to signal for the end of a bus cycle. | ||||||||||||
|
|
|
|
|
|
|
|
|
|
|
| ARDY or SRDY must be active to terminate any processor bus cycle, | ||||
|
|
|
|
|
|
|
|
|
|
|
| unless they are ignored due to correct programming of the Chip Select | ||||
|
|
|
|
|
|
|
|
|
|
|
| Unit. | ||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| ||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
DEN | O | H(Z) |
| Data ENable output to control the enable of bidirectional transceivers | ||||||||||||
|
|
|
|
|
|
|
|
|
| R(Z) |
| when buffering a system. DEN is active only when data is to be | ||||
|
|
|
|
|
|
|
|
|
| P(1) |
| transferred on the bus. | ||||
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||
DT/R | O |
| H(Z) | Data Transmit/Receive output controls the direction of a bi- | ||||||||||||
|
|
|
|
|
|
|
|
|
|
| R(Z) | directional buffer in a buffered system. DT/R is only available on the | ||||
|
|
|
|
|
|
|
|
|
|
| P(X) | QFP (EIAJ) package and the SQFP package. | ||||
|
|
|
|
|
|
|
|
|
|
|
| |||||
|
|
|
|
|
|
|
|
|
|
|
|
| ||||
LOCK | O |
| H(Z) | LOCK output indicates that the bus cycle in progress is not to be | ||||||||||||
|
|
|
|
|
|
|
|
|
|
| R(WH) | interrupted. The processor will not service other bus requests (such | ||||
|
|
|
|
|
|
|
|
|
|
| P(1) | as HOLD) while LOCK is active. This pin is configured as a weakly | ||||
|
|
|
|
|
|
|
|
|
|
|
| held high input while RESIN is active and must not be driven low. | ||||
|
|
|
|
|
|
|
|
|
|
| ||||||
HOLD | I | A(L) |
| HOLD request input to signal that an external bus master wishes to | ||||||||||||
|
|
|
|
|
|
|
|
|
|
|
| gain control of the local bus. The processor will relinquish control of | ||||
|
|
|
|
|
|
|
|
|
|
|
| the local bus between instruction boundaries not conditioned by a | ||||
|
|
|
|
|
|
|
|
|
|
|
| LOCK prefix. | ||||
|
|
|
|
|
|
|
|
|
|
| ||||||
HLDA | O |
| H(1) | HoLD Acknowledge output to indicate that the processor has | ||||||||||||
|
|
|
|
|
|
|
|
|
|
| R(0) | relinquished control of the local bus. When HLDA is asserted, the | ||||
|
|
|
|
|
|
|
|
|
|
| P(0) | processor will (or has) floated its data bus and control signals allowing | ||||
|
|
|
|
|
|
|
|
|
|
|
| another bus master to drive the signals directly. | ||||
|
|
|
|
|
|
|
|
|
|
| ||||||
|
|
|
|
|
|
|
|
|
|
|
| |||||
UCS | O |
| H(1) | Upper Chip Select will go active whenever the address of a memory | ||||||||||||
|
|
|
|
|
|
|
|
|
|
| R(1) | or I/O bus cycle is within the address limitations programmed by the | ||||
|
|
|
|
|
|
|
|
|
|
| P(1) | user. After reset, UCS is configured to be active for memory accesses | ||||
|
|
|
|
|
|
|
|
|
|
|
| between 0FFC00H and 0FFFFFH. During a processor reset, UCS and | ||||
|
|
|
|
|
|
|
|
|
|
|
| LCS are used to enable ONCE Mode. | ||||
|
|
|
|
|
|
|
|
|
| |||||||
|
|
|
|
|
|
|
|
|
|
| ||||||
LCS | O |
| H(1) | Lower Chip Select will go active whenever the address of a memory | ||||||||||||
|
|
|
|
|
|
|
|
|
|
| R(1) | bus cycle is within the address limitations programmed by the user. | ||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| P(1) | LCS is inactive after a reset. During a processor reset, UCS and LCS | ||||
|
|
|
|
|
|
|
|
|
|
|
| are used to enable ONCE Mode. | ||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
NOTE:
Pin names in parentheses apply to the 80C188EA and 80L188EA.
13
13