C8051F540-TB Silicon Laboratories Inc, C8051F540-TB Datasheet - Page 37

• Manufacturer Part Number: C8051F540-TB
• Description: BOARD PROTOTYPE W/C8051F540
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F540-TB

• Contents: Board
• Processor To Be Evaluated: C8051F54x
• Processor Series: C8051F54x
• Interface Type: USB
• Operating Supply Voltage: 5 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: C8051F54x
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1672

5.3.2. Setting the Gain Value
The three programmable gain registers are accessed indirectly using the ADC0H and ADC0L registers
when the GAINEN bit (ADC0CF.0) bit is set. ADC0H acts as the address register, and ADC0L is the data
register. The programmable gain registers can only be written to and cannot be read. See Gain Register
Definition 5.1, Gain Register Definition 5.2, and Gain Register Definition 5.3 for more information.
The gain is programmed using the following steps:
1. Set the GAINEN bit (ADC0CF.0)
2. Load the ADC0H with the ADC0GNH, ADC0GNL, or ADC0GNA address.
3. Load ADC0L with the desired value for the selected gain register.
4. Reset the GAINEN bit (ADC0CF.0)
Notes:
In code, changing the value to 0.44 gain from the previous example looks like:
// in ‘C’:
ADC0CF |= 0x01;
ADC0H = 0x04;
ADC0L = 0x6C;
ADC0H = 0x07;
ADC0L = 0xA0;
ADC0H = 0x08;
ADC0L = 0x01;
ADC0CF &= ~0x01;
; in assembly
ORL ADC0CF,#01H
MOV ADC0H,#04H
MOV ADC0L,#06CH
MOV ADC0H,#07H
MOV ADC0L,#0A0H
MOV ADC0H,#08H
MOV ADC0L,#01H
ANL ADC0CF,#0FEH
1.
2.
An ADC conversion should not be performed while the GAINEN bit is set
Even with gain enabled, the maximum input voltage must be less than V
voltage of the signal after gain must be less than or equal to V
// GAINEN = 1
// GAINEN = 0
// Load the ADC0GNH address
// Load the upper byte of 0x6CA to ADC0GNH
// Load the ADC0GNL address
// Load the lower nibble of 0x6CA to ADC0GNL
// Load the ADC0GNA address
// Set the GAINADD bit
; GAINEN = 1
; Load the ADC0GNH address
; Load the upper byte of 0x6CA to ADC0GNH
; Load the ADC0GNL address
; Load the lower nibble of 0x6CA to ADC0GNL
; Load the ADC0GNA address
; Set the GAINADD bit
; GAINEN = 0
Rev. 1.1
REF
.
REGIN
.
C8051F54x
and the maximum
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