AN2131QC Cypress Semiconductor Corp, AN2131QC Datasheet - Page 135

• Manufacturer Part Number: AN2131QC
• Description: IC MCU 8051 8K RAM 24MHZ 80BQFP
• Manufacturer: Cypress Semiconductor Corp
• Series: EZ-USB®r

Specifications of AN2131QC

• Applications: USB Microcontroller
• Core Processor: 8051
• Program Memory Type: ROMless
• Controller Series: AN213x
• Ram Size: 8K x 8
• Interface: I²C, USB
• Number Of I /o: 24
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 80-QFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 428-1307

The CONTROL transaction starts in the usual way, with the EZ-USB core transferring the
eight bytes in the SETUP packet into RAM at SETUPDAT and activating the SUDAV
interrupt request. The 8051 decodes the Get_Descriptor request, and responds by clearing
the HSNAK bit (by writing “1” to it), and then loading the SUDPTR registers with the
address of the requested descriptor. Loading the SUDPTRL register causes the EZ-USB
core to automatically respond to two IN transfers with 64 bytes and 27 bytes of data using
SUDPTR as a base address, and then to respond to (ACK) the STATUS stage.
The usual endpoint zero interrupts, SUDAV and EP0IN, remain active during this auto-
mated transfer. The 8051 normally disables these interrupts because the transfer requires
no 8051 intervention.
Three types of descriptors are defined: Device, Configuration, and String.
7.3.4.1
As illustrated in Figure 7-5, the 8051 loads the 2-byte SUDPTR with the starting address
of the Device Descriptor table. When SUDPTRL is loaded, the EZ-USB core performs
the following operations:
Page 7-14
1. Reads the requested number of bytes for the transfer from bytes 6 and 7 of the
2. Reads the requested string’s descriptor to determine the actual string length.
3. Sends the smaller of (a) the requested number of bytes or (b) the actual number of
SETUP packet (LenL and LenH in Table 7-11).
bytes in the string, over IN0BUF using the Setup Data Pointer as a data table
Get Descriptor-Device
Byte
0
1
2
3
4
5
6
7
bmRequestType
bRequest
wValueL
wValueH
wIndexL
wIndexH
wLengthL
wLengthH
Field
Table 7-10. Get Descriptor-Device
Value
LenH
LenL
0x80
0x06
0x01
0x00
0x00
0x00
Chapter 7. EZ-USB CPU
IN, Device
“Get_Descriptor”
Descriptor Type:
Device
Meaning
Set SUDPTR H-L to start of
Device Descriptor table in RAM
8051 Response
EZ-USB TRM v1.9