ia186xl Innovasic Semiconductor Inc., ia186xl Datasheet - Page 38

• Manufacturer Part Number: ia186xl
• Description: 16-bit Microcontroller
• Manufacturer: Innovasic Semiconductor Inc.

IA186XL/IA188XL
16-Bit Microcontrollers
4.
4.1
Architecturally, the IA186XL and IA188XL microcontrollers include the following functional
modules:
A functional block diagram of the IA186XL/IA188XL is shown in Figure 10. Descriptions of
the functional modules are provided in the following subsections.
4.1.1 Bus Interface Unit
A local bus controller generates the local bus control signals. It also employs a hold/hlda
protocol for relinquishing the local bus to other bus masters. Its outputs can be used to enable
external buffers and to direct the flow of data on and off the local bus. The bus controller is
responsible for generating 20 bits of address, read and write strobes, bus-cycle status information
and data. This controller is also responsible for reading data from the local bus during a read
operation. Synchronous and asynchronous ready input pins are provided to extend a bus cycle
beyond the minimum four clocks. The bus controller also generates two control signals (den_n
and dt/r_n) when interfacing to external transceiver chips. This capability allows the addition of
transceivers for simple buffering of the multiplexed address/data bus. During reset, the local bus
controller performs the following actions:
1. Drives den_n, rd_n, and wr_n HIGH for one clock cycle, then floats them
2. Drives s0_n ±s2_n to the inactive state (all HIGH) and then floats
3. Drives lock_n HIGH and then floats
4. Floats ad0–15 (ad0–8), a16–19 (a9–a19), bhe_n (rfsh_n), dt/r_n
5. Drives ale LOW
6. Drives hlda LOW
Functional Description
Device Architecture
Bus Interface Unit
Clock Generator
Interrupt Control Unit
Timer/Counter Unit
Chip-Select Unit
Refresh Control Unit
Power-Save Control
DMA Unit
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Page 38 of 72
Preliminary Data Sheet
September 30, 2008
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