HFC-Smini Cologne Chip AG, HFC-Smini Datasheet - Page 12

• Manufacturer Part Number: HFC-Smini
• Manufacturer: Cologne Chip AG

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3.1
The HFC-S mini has an integrated 8 bit microprocessor interface. It is compatibel with Motorola bus and
Intel bus. The different microprocessor interface modes are selected during power on by ALE (see also
1.3 Processor interface modes on page 8).
In mode 2 (Motorola bus mode) and mode 3 (de-multiplexed Intel bus mode) pin A0 is the address input.
The data bus is D[7:0].
In mode 4 (multiplexed Intel bus mode) D[7:0] is the multiplexed address/data bus. A0 must be '0' in this
mode.
3.1.1 Register access
In mode 2 and mode 3 the HFC-S mini has 2 addresses. The lower address (A0 = '0') is used for data
read/write. The higher address (A0 = '1') is write only and is used for register selection. Registers are
selected by first setting A0 to '1' and then writing the address of the desired register to the data bus
D[7:0]. All following accesses to the HFC-S mini with A0 = '0' are read/write operations to this register.
In mode 4 all registers can be directly accessed by their address.
The function of the control signals is shown in the table below.
Table 1: Function of the microprocessor interface control signals
X = don't care
*)
Except in mode 4 ALE is assumed to be stable after RESET.
1-pulse latches register address.
/RD
/DS
X
1
0
0
0
1
0
1
Functional description
Microprocessor interface
/WR
R/W
X
1
1
0
1
0
1
0
/CS
X
1
0
0
0
0
0
0
ALE
0
0
X
X
1
1
0
0
*)
*)
Operation
write data
write data
write data
no access
no access
read data
read data
read data
Mode
all
all
2
3
4
2
3
4
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