Case Example- Zoran Video Inlet Reference Design

Converting from Intel 8x930Ax to Cypress EZ-USB

Table 2. Product Options

		RAM	I/O Rate	# of Prog	8-bit	ISO
Part Number	Package	Size	(Bytes/s)	I/Os	Databus?	Support?

AN2121SC	44 PQFP	4K	600K	16	No	Yes

AN2122SC	44 PQFP	4K	600K	16	No	No

AN2122TC	48 TQFP	4K	600K	19	No	No

AN2125SC	44 PQFP	4K	2M	8	Yes	Yes

AN2126SC	44 PQFP	4K	2M	8	Yes	No

AN2126TC	48 TQFP	4K	2M	11	Yes	No

AN2131SC	44 PQFP	8K	600K	16	No	Yes

AN2135SC	44 PQFP	8K	2M	8	Yes	Yes

AN2136SC	44 PQFP	8K	2M	8	Yes	No

AN2131QC	80 PQFP	8K	2M	24	Yes+Addr	Yes

10.Passive Networks

Both the 8x930Ax and EZ-USB have active-HIGH RESET pins, but while the 8x930Ax requires only a capacitor to VCC, the EZ-USB family parts require a resistor-capacitor network.

11.Connect any programmable I/Os that were used to gen- erate I2C signals directly to the EZ-USB I2C port.

If a peripheral required an I2C bus master, the 8x930Ax would require the use of a programmable I/O along with the appropriate firmware to emulate the I2C bus. EZ-USB has a dedicated I2C port that is a master and can be used to control other I2C devices on the peripheral board.

Additional Firmware Issues To Consider When Converting

1.Compile as 8051 (not 251)

Since the EZ-USB core operates in the 8051 mode only, you must recompile your application in only this configura- tion. The ‘251 mode uses different instructions and formats and will not work. Most compilers for the 8051 family have compile switches that make this translation transparent.

2.Add EZ-USB frameworks code

•Handles endpoint 0 transfers (getdesc… )

•Provides hooks to USB events

•Performs ReNumeration

All of the firmware that is required to handle default device requests, set up the processor environment, perform Re- Numeration, and set up hooks to all of the USB events is included in the Application Frameworks which is included in the EZ-USB Developer’s Kit. Although much of the end- point 0 traffic is handled by the EZ-USB Smart core, the 8051 still has USB overhead to handle. The frameworks code serves as a good example of how to handle the re- maining processing necessary by the 8051.

3.Remove control transfer code

Since the EZ-USB Smart core automatically handles much of the Endpoint 0 Control transfer processing, a good portion of the firmware required by the 930 can be removed from the code after conversion.

4.Use Turbo transfer mode when USB performance is desired

To utilize the full bandwidth of the USB and still achieve the maximum processing power, all data transfers for high-bandwidth data should use the Turbo transfer mode. The firmware required to perform these transfers is very simple and is written in assembly to utilize the full speed of this mode. These transfers will replace standard XDATA accesses in the 930 firmware.

5.Remove 251 configuration setup

Since there are no configuration features that require set- up for the 8051, the configuration setup code for the ‘251 can be removed.

6.Endpoint data is in RAM, not FIFOs

The 930 provides all of the bulk endpoint data in FIFOs, making the processor read each byte out in series to pro- cess a block of endpoint data. The EZ-USB architecture places its data in RAM, which can be accessed in any order necessary. This process can greatly reduce the pro- cessing overhead, especially when processing control transfers.

7.EZ-USB registers are in XDATA space, not SFRs

All of the registers in the EZ-USB chip are contained in the XDATA memory space. This requires MOVX instructions to access them.

8.I/O Ports are in XDATA space

The Intel 8x930Ax family uses SFR (Special Function Register) bits to control their I/O port pins. The EZ-USB family memory maps I/O port control registers, accessible with MOVX instructions. Thus bit set and clear instructions cannot be used with the EZ-USB I/O Ports.