Datasheet

FS98O22
Rev. 1.6 75/146
7.1. Digital I/O Port with Analog Input Channel Shared: PT1[7:0]
Figure 7-1 PT1[7:0] function block
GPIO Port 1 (PT1[7:0]) function block is shown in Figure 7-1. The main function of the GPIO is for data
exchange between the Data bus and the ports. Users could control the PT1EN[7:0] register flags to decide the
input and output direction. The input and output function and the related functions are explained as follows:
z Input:
GPIO Port 1 Bit0 to Bit7 (PT1[7:0]) could be used to get both the digital signal and the analog signal. User
should control the AIENB[7:0] register flags to decide the input type. If user sets the AIENB, the AND gate
embedded in the GPIO Port1 will allow the digital data to connect to the data bus. Otherwise, the Input
signals will be defined as analog signals and sent to the related function blocks (ADC, OPAMP…etc)
z Output
FS98O22 sends the digital data out by an embedded D Flip Flop. When the program sends data out
through PT1, the data will be sent to data bus first, and then the D Flip Flop will latch the signal for PT1
output while the Write signal and AR (FS98O22 internal device address pointer) is pointed to PT1.
z Pull up resistor
FS98O22 embeds an internal pull up resistor function in PT1 with about 1000k ohm resistor
9
. Users
could control the PT1PU[7:0] register flags to decide the connections to pull up resistor. When a port is
connected to the pull up resistor, the input data is, by default, assigned to high (data 1).
9
The pull up current is about 10uA. Remember to disable PT1PU before program falls into Sleep mode.
FORTUNE'
Properties
For Reference Only