S50 Hardware User Guide
1VV0301505 Rev. 1
Page
17
of
53
2018-03-02
If I/O line availability at the host side is extremely tight, 2 I/O lines could be saved by using
the following scheme. This would come at the cost of
•
The host is not allowed to enter sleep mode.
•
The host must accept incoming data at all times and is not able to stop the
Sx sending data. This may be difficult to control for all scenarios and
adds the risk that data gets lost.
•
The host doesn’t implement UICP, but wake-up BT via GPIO.
UART-TXD
GND
UART-RXD
IUC_IN# / CTS#
UART-RXD
UART-TXD
Bl
ueM
od
+S
x
Ho
st
RTS#
CTS#
IUC_OUT# / RTS#
IUR_OUT#
IUR_IN#
BM+Sx-WKUP
Figure 8: Five Wire Interface supporting UICP
4.3.4.
Dynamic I/O Signal Type Changes Depending on UICP Status
In order to reduce current consumption when using UICP, the S50 FW supports
the following dynamic I/O signal type changes depending on the UICP activated resp.
deactivated status.
Signal
UICP deactivated
UICP activated
UART-CTS#
I-PD
I-FLOAT
IUR-IN#
I-DIS
I-FLOAT
IUR-OUT#
I-DIS
O-PP
(1)
I-PU: input pull-up; I-PD: input pull-down; I-FLOAT: input floating; I-DIS: input disconnected; O-PP: output push-pull
Table 2: Pin Assignments
Signal types I-PD, I-DIS and O-PP may be left open. I-FLOAT has to be driven to GND or
VCC to avoid open CMOS input oscillation.
If UICP is deactivated the pull-down resistor on UART-CTS# helps to keep the serial
interface active if UART-CTS# is open.
If UICP is active and the serial interface is down, UART-CTS# has to be held at VCC and
thus the pull-down would cause an unwanted permanent current drain. Therefore, the pull-
down is switched off in this mode.
Summary of Contents for BlueMod+S50/AI
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