ZHCSVJ2I August 2007 – December 2024 CDCE937 , CDCEL937
PRODUCTION DATA
The CDCEx937 has three user-definable control terminals (S0, S1, and S2) which allow external control of device settings. The terminals can be programmed to any of the following setting:
The user can predefine up to eight different control settings. Table 7-1 and Table 7-2 explain these settings.
| EXTERNAL CONTROL BITS | PLL1 SETTING | PLL2 SETTING | PLL3 SETTING | Y1 SETTING | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Control Function | PLL Frequency Selection | SSC Selection | Output Y2/Y3 Selection | PLL Frequency Selection | SSC Selection | Output Y4/Y5 Selection | PLL Frequency Selection | SSC Selection | Output Y6/Y7 Selection | Output Y1 and Power-Down Selection |
| SSC SELECTION (CENTER/DOWN)(1) | ||||
|---|---|---|---|---|
| SSCx [3-bits] | CENTER | DOWN | ||
| 0 | 0 | 0 | 0% (off) | 0% (off) |
| 0 | 0 | 1 | ±0.25% | –0.25% |
| 0 | 1 | 0 | ±0.5% | –0.5% |
| 0 | 1 | 1 | ±0.75% | –0.75% |
| 1 | 0 | 0 | ±1% | –1% |
| 1 | 0 | 1 | ±1.25% | –1.25% |
| 1 | 1 | 0 | ±1.5% | –1.5% |
| 1 | 1 | 1 | ±2% | –2% |
| FREQUENCY SELECTION(2) | ||||
| FSx | FUNCTION | |||
| 0 | Frequency0 | |||
| 1 | Frequency1 | |||
| OUTPUT SELECTION(3) (Y2 ... Y7) | ||||
| YxYx | FUNCTION | |||
| 0 | State0 | |||
| 1 | State1 | |||
| Y1 SELECTION | |
|---|---|
| Y1 | FUNCTION |
| 0 | State 0 |
| 1 | State 1 |
S1/SDA and S2/SCL pins of the CDCEx937 are dual function pins. In default configuration the pins are defined as SDA/SCL for the serial interface. The pins can be programmed as control-pins (S1/S2) by setting the relevant bits in the EEPROM. Note that the changes to the Control register (Bit [6] of Byte [02]) have no effect until the pins are written into the EEPROM.
Once the pins are set as control pins, the serial programming interface is no longer available. However, if VDDOUT is forced to GND, the two control-pins, S1 and S2, temporally act as serial programming pins (SDA/SCL).
S0 is not a multi-use pin, the pin is a control pin only.