TC1796
Peripheral Units (Vol. 2 of 2)
General Purpose Timer Array (GPTA)
User’s Manual
24-255
V2.0, 2007-07
GPTA, V2.0
24.6.3.4 Emergency Control of GPTA Output Ports Lines
Port lines connected to GPTA output pins can be selectively switched into an Emergency
Mode. In this mode, GPTA output pins react immediately to an active input signal P10.1
(HWCFG1) and drive a logic level that has been programmed in the port output register.
As a result, in Emergency Mode a GPTA output pin drives a predefined value instead of
the corresponding logic level that is provided on the related GPTA module output line.
All GPTA pins at Port 2, Port 3, Port 4, Port 8, and Port 9 are connected to one common
emergency stop signal that is generated in the System Control Unit of the TC1796. More
details about the generation of this emergency stop signal are described in the “System
Control Unit” chapter of the TC1796 System Units User’s Manual.
The emergency stop signal always controls 8-bit groups of port lines. The enable
function is controlled for each pin by bits ENy (y = number of port line) which are located
in the Px_ESR (x = port number) registers. When the emergency stop signal generated
in the SCU becomes active and bit Px_ESR.ENy set, output line Px.y is set to the value
of register Px_OUT.Py (emergency enabled). Output Px.y is not affected by the
emergency stop signal when bit Px_OUT.Py is reset (emergency disabled).
When the emergency stop signal is released, Pin x.y is switched back to the previously
selected GPTA output function without reprogramming the related port registers.
The emergency stop enable bits ENy are implemented only for output pins at Port 2,
Port 3, Port 4, Port 8, and Port 9 that can be connected to the GPTA module.
Table 24-28 Emergency Control for GPTA Port Output Lines
Port
ESR
Register
ESR
Enable Bits
GPTA Output Lines
Port 2
P2_ESR
EN[15:8]
OUT[7:0]
Port 3
P3_ESR
EN[15:0]
OUT[23:8]
Port 4
P4_ESR
EN[15:0]
OUT[39:24]
Port 8
P8_ESR
EN[7:0]
OUT[47:40]
Port 9
P9_ESR
EN[7:0]
OUT[55:48]
