FS98O21 datasheet(67/136 Pages) FORTUNE

67 / 136 page

FS98O21

Rev. 1.7

67/136

Input:

GPIO Port 2 Bit1 and Bit0 (PT2[1:0]) could be the external interrupt ports as INT1 and INT0 or be the

general I/O ports. User should control INTE register E0IE and E1IE flags to decide if the interrupt is

enabled. The interrupt trigger mode is selected by E0M[1:0] and E1M[1:0] register flags. The input port

has a Schmitt trigger in it, and the up/down trigger voltage level is 0.45VDD/0.2VDD.

Output

FS98O21 sends the digital data out by an embedded D Flip Flop. When the program sends data out

through PT2, the data will be sent to data bus first, and then the D Flip Flop will latch the signal for PT2

output while the Write signal and AR (FS98O21 internal device address pointer) is pointed to PT2.

Pull up resistor

FS98O21 embeds an internal pull up resistor function in PT2 with about 1000k ohm resistor

11. Users

could control the PT2PU[1:0] 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).

11 The pull up current is about 10uA. Remember to disable PT1PU before program falls into Sleep mode.

FS98O21 Datasheet(PDF) 67 Page - Fortune Semiconductor Corp.