Datasheet

ManualsBrandsMicrochip ManualsIntegrated Circuits (ICs)USB 2.0 to I²C / UART Converter PDIP

MCP2221

DS20005292A-page 30  2014 Microchip Technology Inc.

7 GP3 Power-up Settings

Bits7-5: Don’t

care

Bit 4: GPIO Output value When GP3 is set as an output GPIO, this value will be present

at the GP3 pin at Power-up/Reset.

Bit 3: GPIO Direction

(Input/Output). Works only when

GP3 is set for GPIO operation

1 GPIO Input mode

0 GPIO Output mode

Bit 2-0: GP1 Designation 111-100 Don’t care

011 Alternate function 2 (DAC2)

010 Alternate function 1 (ADC3)

001 Dedicated function operation (LED I2C)

000 GPIO operation

8-63 Don’t

care

TABLE 3-7: RESPONSE STRUCTURE – READ USB MANUFACTURER DESCRIPTOR STRING

SUB-COMMAND

Byte Index Value Effect

0 0xB0 Read Flash Data – command code echo

1 0x00 Command completed successfully

(2)

Number of bytes + 2 in the provided USB Manufacturer

Descriptor String. The actual String starts at Byte Index 4.

3 0x03 The value at this index must always be 0x03.

4 + 2 x Unicode_char_number + 0

(1)

Lower byte of the 16-bit Unicode character.

4 + 2 x Unicode_char_number + 1

(1)

Higher byte of the 16-bit Unicode character.

(4 + 2 x Unicode_char_number + 2) - 63

(1)

Don’t care. Only if the USB string descriptor is less than 60-bytes

long in total.

Note 1: “Unicode_char_number” value starts from 0 to a maximum of 30 (included).

2: The value at Byte Index 2 must be 2 + 2 x (number of Unicode characters in the string).

TABLE 3-8: RESPONSE STRUCTURE – READ USB PRODUCT DESCRIPTOR STRING

SUB-COMMAND

Byte Index Value Effect

0 0xB0 Read Flash Data – command code echo

1 0x00 Command completed successfully

(2)

Number of bytes + 2 in the provided USB Product Descriptor

String. The actual String starts at Byte Index 4.

3 0x03 The value at this index must always be 0x03

4 + 2 x Unicode_char_number + 0

(1)

Lower byte of the 16-bit Unicode character.

4 + 2 x Unicode_char_number + 1

(1)

Higher byte of the 16-bit Unicode character.

(4 + 2 x Unicode_char_number + 2) - 63

(1)

Don’t care. Only if the USB string descriptor is less than

60-bytes long (in total).

Note 1: “Unicode_char_number” value starts from 0 to a maximum of 30 (included).

2: The value at Byte Index 2 must be 2 + 2 x (number of Unicode characters in the string).

TABLE 3-6: RESPONSE STRUCTURE – READ GP SETTINGS SUB-COMMAND (CONTINUED)

Byte

Index

Function Description Value Effect