English
Language : 

AK7755EN_16 Datasheet, PDF (95/109 Pages) Asahi Kasei Microsystems – DSP with Mono ADC Stereo CODEC + Mic/Lineout Amp
◁
[AK7755]
■ EEPROM Interface
1. Data Download
The AK7755 has EEPROM boot mode to read out necessary data from an external EEPROM to the
internal memory via I2C bus. A hands-free function is easily realized in the system using EEPROM
without extra overloads on the microprocessor. The external EEPROM should be connected to the I2C
interface of the AK7755 (I2CSEL pin= “H”). A SPI interface type EEPROM cannot be connected. Write
data as shown in “2. Program Map” to the EEPROM.
Control registers can shift the WRITE command code and data in 2 BYTE unit. However, the data
location from the PRAM WRITE command code (0034h) to OFREG address 31LSB (689Ch) is fixed.
Set “1010000” to I2C slave address of the EEPROM when 256K bit, and set “101000+A16” when 1M
bit.
The AK7755 starts downloading the data from the EEPROM when setting the EXTEEP pin to “H” or
DLS bit (CONT0D: D0) to “1” while the EXTEEP pin = “L” after inputting a 12.288MHz clock to the
XTI pin or connecting a 12.288MHz crystal oscillator to the XTI pin and the XTO pin. The EEST
(SDOUT1) pin goes to “H” while downloading data and the AK7755 becomes an I2C master. Do not
write/read to the other devices that are connected to the same I2C bus during downloading. The EEST
pin returns to “L” after downloading data and the AK7755 will be in I2C slave mode. Interfacing to a
microcontroller becomes available when the EEST pin = “L”.
When accessing the AK7755 after downloading data by CRC function, set CRCE bit (CONT10: D6) to
“0” before access the AK7755. The EEPROM download period is 0.8s (max). Set the EXTEEP pin “H”
→ “L” → “H” or DLS bit (CONT0D, D0) “1” → “0” → “1” to start a data downloading again.
However, data downloading cannnot be executed by DLS bit when selecting memory mat (I2CSEL pin
= MATSEL pin = “H”).
Control
μP/
EEPROM
Interface
STO
EEST (SDOUT1)
SCL
SDA
EEPROM
SCL
SDA
EXTEEP
I2CSEL= “H”
PDN
Control
STO
EEST (SDOUT1)
μP/
EEPROM SCL
Interface
SDA
EXTEEP
I2CSEL = “H”
PDN
μP
GPI1
GPI2
SCL
SDA
EEPROM
SCL
SDA
Figure 75. EEPROM Connection (Left: EEPROM only, Right: CPU and EEPROM)
014006643-E-00
- 95 -
2014/10
 ▷