FMS6501
—
12
Input
/
9
Output
V
ideo
Switch
Matrix
with
I
nput
Clamp,
Input
Bias
Circ
uitry
,and
Output
Drivers
2004 Fairchild Semiconductor Corporation
www.fairchildsemi.com
FMS6501 Rev. 1.0.4
5
Digital Interface
The I2C-compatible interface is used to program output
enables, input to output routing, input clamp / bias, and
output gain. The I2C address of the FMS6501 is 0x06
(0000 0110) with the ability to offset it to 0x86 (1000
0110) by tying the ADDR pin high.
Both data and address data, of eight bits each, are writ-
ten to the I2C address to access all the control functions.
There are separate internal addresses for each output.
Each output’s address includes bits to select an input
channel, adjust the output gain, and enable or disable
the output amplifier. More than one output can select the
same input channel for one-to-many routing. When the
outputs are disabled, they are placed in a high-imped-
ance state. This allows multiple FMS6501 devices to be
paralleled to create a larger switch matrix. Typical output
power-up time is less than 500ns.
The clamp / bias control bits are written to their own
internal address, since they should always remain the
same regardless of signal routing. They are set based on
the input signal connected to the FMS6501.
All undefined addresses may be written without effect.
Output Control Register Contents and Defaults
Notes:
1. Power down places the output in a high-impedance state so multiple FMS6501 devices may be paralleled. Power
down also de-selects any input routed to the specified output.
2. When all inputs are OFF, the amplifier input is tied to approximately 150mV and the output goes to approximately
300mV with the 6dB gain setting.
Output Control Register MAP
Notes:
1. IN4 is provided for forward compatibility and should always be written as ‘0’ in the FMS6501.
Clamp Control Register Contents and Defaults
Clamp Control Register Map
Control Name
Width
Type
Default
Bit(s)
Description
Enable
1 bit
Write
0
7
Channel Enable: 1=Enable, 0=Power Down(1)
Gain
2 bits
Write
0
6:5
Channel Gain: 00=6dB, 01=7dB, 10=8dB, 11=9dB
Inx
5 bits
Write
0
4:0
Input selected to drive this output: 00000=OFF(2),
00001=IN1, 00010=IN2... 01100=IN12
Register
Name
Register
Address
Bit 7
Bit 6
Bit5
Bit4(1)
Bit3
Bit2
Bit1
Bit0
OUT1
0x01
Enable
Gain1
Gain0
IN4
IN3
IN2
IN1
IN0
OUT2
0x02
Enable
Gain1
Gain0
IN4
IN3
IN2
IN1
IN0
OUT3
0x03
Enable
Gain1
Gain0
IN4
IN3
IN2
IN1
IN0
OUT4
0x04
Enable
Gain1
Gain0
IN4
IN3
IN2
IN1
IN0
OUT5
0x05
Enable
Gain1
Gain0
IN4
IN3
IN2
IN1
IN0
OUT6
0x06
Enable
Gain1
Gain0
IN4
IN3
IN2
IN1
IN0
OUT7
0x07
Enable
Gain1
Gain0
IN4
IN3
IN2
IN1
IN0
OUT8
0x08
Enable
Gain1
Gain0
IN4
IN3
IN2
IN1
IN0
OUT9
0x09
Enable
Gain1
Gain0
IN4
IN3
IN2
IN1
IN0
Control Name
Width
Type
Default
Bit(s)
Description
Clmp
1 bit
Write
0
7:0
Clamp / Bias selection: 1 = Clamp, 0 = Bias
Register Name
Register
Address
Bit 7
Bit 6
Bit5Bit4Bit3Bit2Bit1Bit0
CLAMP1
0x1D
Clmp8
Clmp7
Clmp6
Clmp5
Clmp4
Clmp3
Clmp2
Clmp1
CLAMP2
0x1E
Resv’d
Clmp12
Clmp11
Clmp10
Clmp9