Cypress CY7C68013A manual Applications, Functional Overview

CY7C68013A, CY7C68014A CY7C68015A, CY7C68016A

2. Applications

■Portable video recorder

■MPEG/TV conversion

■DSL modems

■ATA interface

■Memory card readers

■Legacy conversion devices

■Cameras

■Scanners

■Home PNA

■Wireless LAN

■MP3 players

■Networking

The “Reference Designs” section of the Cypress web site provides additional tools for typical USB 2.0 applications. Each reference design comes complete with firmware source and object code, schematics, and documentation. Visit the Cypress web site for more information.

3. Functional Overview

3.1 USB Signaling Speed

FX2LP operates at two of the three rates defined in the USB Specification Revision 2.0, dated April 27, 2000:

■Full-speed, with a signaling bit rate of 12 Mbps

■High-speed, with a signaling bit rate of 480 Mbps.

FX2LP does not support the low speed signaling mode of 1.5 Mbps.

3.2 8051 Microprocessor

The 8051 microprocessor embedded in the FX2LP family has 256 bytes of register RAM, an expanded interrupt system, three timer/counters, and two USARTs.

3.2.1 8051 Clock Frequency

FX2LP has an on-chip oscillator circuit that uses an external 24 MHz (±100 ppm) crystal with the following characteristics:

■Parallel resonant

■Fundamental mode

■500-μW drive level

■12-pF (5% tolerance) load capacitors

An on-chip PLL multiplies the 24 MHz oscillator up to 480 MHz, as required by the transceiver/PHY and internal counters divide it down for use as the 8051 clock. The default 8051 clock

frequency is 12 MHz. The clock frequency of the 8051 can be changed by the 8051 through the CPUCS register, dynamically.

Figure 1. Crystal Configuration

C1 24 MHz C2

12 pf 12 pf

20 × PLL

12-pF capacitor values assumes a trace capacitance

of 3 pF per side on a four-layer FR4 PCA

The CLKOUT pin, which can be three-stated and inverted using internal control bits, outputs the 50% duty cycle 8051 clock, at the selected 8051 clock frequency: 48 MHz, 24 MHz, or 12 MHz.

3.2.2 USARTS

FX2LP contains two standard 8051 USARTs, addressed via Special Function Register (SFR) bits. The USART interface pins are available on separate IO pins, and are not multiplexed with port pins.

UART0 and UART1 can operate using an internal clock at 230 KBaud with no more than 1% baud rate error. 230 KBaud operation is achieved by an internally derived clock source that generates overflow pulses at the appropriate time. The internal clock adjusts for the 8051 clock rate (48 MHz, 24 MHz, and 12 MHz) such that it always presents the correct frequency for 230 KBaud operation.[1]

3.2.3 Special Function Registers

Certain 8051 SFR addresses are populated to provide fast access to critical FX2LP functions. These SFR additions are shown in Table 1 on page 4. Bold type indicates non standard, enhanced 8051 registers. The two SFR rows that end with “0” and “8” contain bit addressable registers. The four IO ports A to D use the SFR addresses used in the standard 8051 for ports 0 to 3, which are not implemented in FX2LP. Because of the faster and more efficient SFR addressing, the FX2LP IO ports are not addressable in external RAM space (using the MOVX instruction).

3.3 I2C Bus

FX2LP supports the I2C bus as a master only at 100-/400- KHz. SCL and SDA pins have open-drain outputs and hysteresis inputs. These signals must be pulled up to 3.3V, even if no I2C device is connected.

3.4 Buses

All packages, 8-bit or 16-bit “FIFO” bidirectional data bus, multi- plexed on IO ports B and D. 128-pin package: adds 16-bit output-only 8051 address bus, 8-bit bidirectional data bus.

Note

1. 115 KBaud operation is also possible by programming the 8051 SMOD0 or SMOD1 bits to a “1” for UART0, UART1, or both respectively.

Document #: 38-08032 Rev. *L Page 3 of 62

[+] Feedback