CRD5463PM

DS805RD2

5

2.5 ATtiny2313 Microcontroller

In addition to the CS5463 on the daughter board, an Atmel™ ATtiny2313 microcontroller is used to initial-

ize the CS5463, convert the SPI into UART, and provide nonvolatile memory for the calibrations.

The ATtiny2313 is an MCU with SPI and UART interfaces, 2 kB Flash program memory and 128 bytes

EEPROM data memory. The MCU acts as a communication bridge between the CS5463’s SPI interface

and the UART of the UART-to-USB converter. The EEPROM data memory is used to store calibration

information.

The hardware connections between the ATtiny2313 and the CS5463 are RESET, SCLK, CS, SDI, SDO,

INT (interrupt), and connection-configurable clock signals. Through the population of the 0 ohms resistor

R15 or R16, the clock source can be shared between the CS5463 and the ATtimy2313. In the current

version of the CRD5463PM, the CS5463 and ATtiny2313 are configured to use their own clock sources.

The CS5463 uses a 4.096 MHz crystal and the ATtiny2313 uses its internal 8 MHz R-C oscillator.

On the daughter board, connector J4 is provided for programming and debugging the ATtiny2313 MCU.

WARNING

High Voltage Hazard

The signal ground for the daughter board is the power line.

DO NOT CONNECT ANY DEBUGGING OR PROGRAMMING TOOLS TO THE J4 CONNECTOR WHEN

AC LINE POWER IS CONNECTED.

Please consult with Cirrus Logic engineering if re-programming the MCU is desired.

For more detailed information of ATtiny 2313, please refer to the ATtiny2313 datasheet.

2.6 Isolated UART

Because the CRD5463PM uses non-isolated components as the current and voltage sensors, the signal

ground of the CS5463 and MCU is the live connection to the main power. However, the signal ground of

the PC USB port is normally chassis ground or earth ground. The electrical isolation must be fulfilled on

the UART communication interface to allow the CRD5463PM to be connected to a PC through a USB

cable without short-circuit and safety problems. The CRD5463PM uses 2 opto-couplers to isolate the

UART interface. The isolation rating is 5300 V RMS.

2.7 UART-USB Interface- FT232R

A USB-to-UART interface IC, FT232R, is used on the main board to interface the CRD to a PC as a virtual

COM port through the USB connection.

3. SOFTWARE CONTROL

The CRD5463PM comes with GUI software and a USB cable to link the CRD to a PC. The GUI was de-

veloped with Lab Windows™/CVI™, a software development package from National Instruments Corpo-

ration. The GUI software is available for download on the Cirrus Logic web site at:

http://www.cirrus.com/industrialsoftware