Datasheet
CONTROL BYTE
TSC2008
SBAS406B – JUNE 2008 – REVISED MARCH 2009 ..........................................................................................................................................................
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The control byte (on SDI), as shown in Table 2 , provides the start conversion, addressing, A/D converter
resolution, configuration, and power-down of the TSC2008. Figure 30 , Table 2 , and Table 3 give detailed
information regarding the order and description of these control bits within the control byte.
Table 2. Order of the Control Bits in the Control Byte
BIT 7 BIT 0
(MSB) BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 (LSB) COMMENT
S A2 A1 A0 MODE SER/ DFR PD1 PD0 Excludes setup command
S 0 1 0 Pull-up Bypass Timing Reset Setup command
Table 3. Description of the Control Bits in the Control Byte
BIT DESCRIPTION
Start Bit. When this bit = '1', it indicates this is one of the user commands. A new control byte can start every 16th clock cycle in
7
12-bit conversion mode or every 12th clock cycle in 8-bit conversion mode (see Figure 30 through Figure 33 ).
Bit[6:4] = A[2:0]. Channel select command if A[2:0] ≠
'010'.
These channel select bits, along with the SER/ DFR bit,
6-4 Bit[6:4] = A[2:0]. Setup command if A[2:0] = '010'.
control the setting of the multiplexer input, touch driver
switches, and reference inputs (see Table 4 and
Figure 30 through Figure 33 ).
Mode Select Bit. This bit controls the number of bits for
Pull-up Resistor Select Bit
(1)
.
the next conversion.
3 0: 50k Ω PENIRQ pull-up resistor (default).
0: 12 bits (low)
1: 90k Ω PENIRQ pull-up resistor.
1: 8 bits (high).
Single-Ended/Differential Reference Select Bit
Bypass Noise Filter Bit
(1)
.
(SER/ DFR). Along with the channel select bits, A[2:0],
2 0: MAV noise filter enabled (default).
this bit controls the setting of the multiplexer input, touch
1: MAV noise filter bypassed.
driver switches, and reference inputs (see Table 4 ).
Bit 1: Timing Select Bit
(1)
.
0: TSC2046-compatible timing for SDO during data read (default)
1: Adjusted SDO timing; MSB appears before 1st rising clock edge.
Bit[1:0] = PD[1:0]. Power Down Mode Select Bits.
1-0
See Table 5 for details.
Bit 0: Software Reset Bit.
0: Nothing happens (default).
1: Software reset.
(1) These bits configure the pull-up resistor value, control the filter bypass, and select the SDO output timing. The bits are static and the
values are stored in register bits that will only be reset to default by a reset condition (power-on reset, software reset, or SureSet) or
changed with the setup command.
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