![]() |
Electronic Components Datasheet Search |
|
EM6617 Datasheet(PDF) 17 Page - EM Microelectronic - MARIN SA |
|
EM6617 Datasheet(HTML) 17 Page - EM Microelectronic - MARIN SA |
17 / 65 page ![]() EM6617 Copyright © 2005, EM Microelectronic-Marin SA 17 www.emmicroelectronic.com 7.4 Port B The EM6617 has one four bit general purpose I/O port. Each bit can be configured individually by software for input/output, pull-up, pull-down and CMOS or Nch. open drain output type. The port outputs either data, frequency or PWM signals. 7.4.1 Input / Output Mode Each port B terminal is bit-wise bi-directional. The input or output mode on each port B terminal is set by writing the corresponding bit in the RegPBCntl control register. To set for input (default), 0 is written to the corresponding bit of the RegPBCntl register which results in a high impedance state for the output driver. The output mode is set by writing 1 in the control register, and consequently the output terminal follows the status of the bits in the RegPBData register. The port B terminal status can be read on address RegPBData even in output mode. Be aware that the data read on port B is not necessary of the same value as the data stored on RegPBData register. See also Figure 13 for details. Figure 13. Port B Architecture Open Drain Option Register Port B Direction Register Port B Data Register Internal Data Bus MUX Active Pull-down I / O Terminal PB[n] PBIOCntl[n] PBData[n] DB[n] Read Read for PB[3:0] Multiplexed Output Multiplexed Output Active Multiplexed Outputs are: PWM, Ck[11], Ck[16], Ck[12] Port B Control Active Pull-up in Nch. Open Drain Mode Read NoPdPB[n] Pull-down Option Register NchOpDPB[n] mask option MPBPD[n] Mask Option MPBPD[n] 4 |