TAS1020 Datasheet, PDF (18/93 Pages) Texas Instruments – USB Streaming Controller

All memory mapped registers are initialized to a default value as defined in Appendix A, MCU Memory and Memory-
Mapped Registers. The TAS1020 device powers up with a default function address of zero and disconnected from
the USB.
2.2.2.1 Boot Load from EEPROM
Loading the application code from an external serial EEPROM requires a preprogrammed memory device containing
an informative header and the application code. While the application code is being downloaded, the TAS1020
remains disconnected from the USB. When the code download is complete, execution of the application code
connects the TAS1020 to the USB. In this situation, the TAS1020 enumerates using the vendor ID and product ID
contained in the application code.
2.2.2.2 EEPROM Header
For both application code and USB device information stored in a EEPROM device, a common header format is used
that precedes the data payload. Table 2-1 shows the format and information contained in the header.
Table 2–1. EEPROM Header
OFFSET
0
1
2
4
6
8
9
10
TYPE
headerChksum
HeaderSize
Signature
VenderID
ProductID
ProductVersion
FirmwareVersion
UsbAttributes
11
MaxPower
12 Attribute
13 WPageSize
14 DataType
15 RpageSize
SIZE
1
1
2
2
2
1
1
1
1
1
1
1
1
VALUE
Check sum of the header by adding the header, excluding the header cheksum, in bytes.
Size of the header including strings if applied
Signature: 0x1234
USB Vendor ID
USB Vendor ID
Product version
Firmware version
USB attributes:
Bit 0: If set to 1, the header includes all three strings: language, manufacture, and product strings, if set
to 0, the header does not include any string.
Bit 2: If set to 1, the device can be self powered, if set to 0, it is not self powered.
Bit 3: If set to 1, the device can be bus powered, if set to 0, it is not be bus powered.
Bit 1 and 4 ... 7: Not used.
Maximum power the device needs in units of 2 mA.
Device attributes:
Bit 3: If set to 1, the devices EEPROM support 400 kHz, if set to 0, it can not support 400 MHz.
Bit 0: If set to 1, the CPU speed runs at 24 MHz, if set to 0, the CPU speed runs at 12 MHz.
Bit 1, 2 and 4 ... 7: Not used.
Maximum I2C write page size
This value defines if the device is application EEPROM, device EEPROM.
0x01: Application EEPROM
0x02: Device EEPROM
Other values are invalid.
Maximum I2C read page size. If the value is zero, the whole payLoadSize is read in one I2C read
setup.
16 payLoadSize
2 Size of the application, if using EEPROM as an application EEPROM, otherwise the value is 0.
0xxx Language string
4 Language string in standard USB string format if applied.
0xxx Manufacture string ... Manufacture string in standard USB string format if applied.
0xxx Product string
... Product string in standard USB string format if applied.
0xxx Application Code
... Application code if applied
The signature field is used for the detection of a EEPROM device connected to the TAS1020. The header size field
supports future updates of the header. Data begins right after the header. The version field identifies the header
version. The EEPROM type field identifies the specific EEPROM device being used. The data type field describes
the nature of data stored in the EEPROM (application code or USB device information). The data size field holds the
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