User's Manual

Bluegiga Technologies Oy
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8 I/O Parallel Ports
The Parallel Input Output (PIO) Port is a general-purpose I/O interface to WT32. The port consists of eleven
programmable, bi-directional I/O lines, PIO[10:0]. Programmable I/O lines can be accessed either through an
embedded application running on WT32 or through private channel or manufacturer-specific HCI commands.
All PIO lines are configured as inputs with weak pull downs at reset.
PIO[2] / USB_PULL_UP (1)
The function depends on whether WT32 is a USB or UART capable version. On UART versions, this terminal
is a programmable I/O. On USB versions, it can drive a pull-up resistor on USB_D+. For applications using
external RAM, this terminal may be programmed for chip select.
PIO[3] / USB_WAKE_UP (1)
On UART versions of WT32, this terminal is a programmable I/O. On USB versions, its function is selected by
setting the Persistent Store Key PSKEY_USB_PIO_WAKEUP (0x2cf) either as a programmable I/O or as a
USB_WAKE_UP function.
PIO[4] / USB_ON (1)
On UART versions of WT32, this terminal is a programmable I/O. On USB versions, the USB_ON function is
also selectable.
PIO[5] / USB_DETACH (1)
On UART versions of WT32, this terminal is a programmable I/O. On USB versions, the USB_DETACH
function is also selectable.
PIO[6] / CLK_REQ
Function is determined by Persistent Store Keys. Using PSKEY_CLOCK_REQUEST_ENABLE, (0x246) this
terminal can be configured to be low when WT32 is in deep sleep and high when a clock is required. The
clock must be supplied within 4ms of the rising edge of PIO[6] to avoid losing timing accuracy in certain
Bluetooth operating modes.
PIO[7]
Programmable I/O terminal.
PIO[8]
Programmable I/O terminal.
PIO[9]
Programmable I/O terminal.
PIO[10]
Programmable I/O terminal.