CN-0164

Circuit Note

Rev. A | Page 4 of 5

DATA I/O

DATA PACKAGE (4 BYTES)

9 CLOCK CYCLES

CRC (2 BYTES)

INT/LOCK

DATA CLK

INTERRUPT FROM ADF7020 TO ADuC7060 IRQ2

INTERRUPTS FROM ADF7020 TO ADuC7060 IRQ3

PACKAGE RECEIVED

Figure 3. Data I/O Timing

ADF7020 INTERRUPT

BIT_CNTR = 0

BIT_CNTR = 0

Rx or Tx?

END OF

PACKAGE?

ALL BYTES

SENT?

BIT_CNTR < 7

BIT_CNTR < 7

CLOCK-IN BIT

FROM ADF7020

STORE BYTE

CLOCK-OUT BIT

TO ADF7020

SET PACKAGE

Rx FLAG

INC. BIT_CNTR

DISABLE INTERRUPT

EXIT INTERRUPT

INC. BIT_CNTR

Rx

Tx

YES

NO

YES

YES

Figure 4. Interrupt Service Routines for Handling Rx and Tx Data