Texas Instruments eZAudio TPA2015D1, Руководство пользователя, Страница: 21 / 24

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Measurements and Calculations on eZAudio TPA2015D1EVM
I2C_SDA, I2C_SCL: Digital POT control
These are the I2C control signals for the 100-k Ω digital potentiometer. The digital potentiometer must be
set to position #41 (VDD=3.6 V) before U6 is enabled. The digital potentiometer sets the feedback voltage
for VDD regulator.
I2C Slave Address: 0x50 (for MSP430 hardware I2C)
Register Address: 0x00 (write/read)
Hexadecimal Code for wiper position #41 (VDD=3.7 V): 0x29
Wiper position can be read back from this register at power up (Nonvolatile).
Allowed wiper range for this application is from #85 (0x55) to #32 (0x20), which corresponds to supply
voltage range 1.8 V to 4.8 V
For the full voltage range use USB power option (batteries give only up to 4.5 V).
For more information on the digital potentiometer, see the TPL0102 data sheet ( SLIS134 ).
Table 2. Control From MSP430 to TPA2015D1
(1)
TPA2015D1 MSP430 MCU
Gain0 P4.1 (pin 44)
Gain1 P4.2 (pin 45)
AGC0 P4.3 (pin 46)
AGC1 P4.4 (pin47)
ENB P4.5 (pin 48)
END P4.6 (pin 49)
REG_EN P4.7 (pin 50)
I2C_SDA P3.1 (pin 34)
I2C_SCL P3.2 (pin 35)
(1)
MSP430 Control signals are +3.3V compatible
A.2 Measurements and Calculations on eZAudio TPA2015D1EVM
• Supply voltage (VDD_AD)
– Measured voltage must be multiplied by 2. VDD = 2 × Vmeas
• Supply current (IDD_AD)
– Is measured as a voltage out of INA333. Idd = Vmeas/4
• Output power
– Is calculated as P = (Voutrms)
2
/ Rload
21 SLOU312 – June 2011 Technical Specifications
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