ZHCSJU4I November 2006 – September 2018 CC1020
PRODUCTION DATA.
The microcontroller interface is shown in Figure 5-3. The microcontroller uses 3 or 4 I/O pins for the configuration interface (PDI, PDO, PCLK and PSEL). PDO should be connected to a microcontroller input. PDI, PCLK and PSEL must be microcontroller outputs. One I/O pin can be saved if PDI and PDO are connected together and a bi-directional pin is used at the microcontroller.
The microcontroller pins connected to PDI, PDO and PCLK can be used for other purposes when the configuration interface is not used. PDI, PDO and PCLK are high impedance inputs as long as PSEL is not activated (active low).
PSEL has an internal pullup resistor and should be left open (tri-stated by the microcontroller) or set to a high level during power down mode in order to prevent a trickle current flowing in the pullup.