GD32W51x User Manual
914
Cycle Num ber
Num ber of ECCLKs in Extend Charge state
…
…
Table 26-3. Spread spectrum deviation base on HCLK period
HCLK Period
Spread spectrum deviation w ith different ECDIV value (ECDT=0x7F)
ECDIV[2:0]=0x0 (Min)
ECDIV[2:0]=0x1
ECDIV[2:0]=0x7(Max)
41.6ns (24MHz)
5333.3ns
10666.6ns
42666.6ns
20.8ns (48MHz)
2666.6ns
5333.3ns
21333.3ns
13.8ns (72MHz)
1777.7ns
3555.5ns
14222.2ns
11.9ns (84MHz)
1523.8ns
3047.6ns
12190.4ns
9.26ns(108MHz)
1185.18ns
2370.37ns
9481.48ns
26.3.6.
PIN mode control of TSI
There are 4 pins in each group and each of these pins is able to be used as a sample pin or
channel pin. Only one pin in a group should be configured as sample pin, and channel pins
can be more than one. The sample pin and channel pin(s) should not be configured as the
same pin in any case.
When a PIN is configured in GPIO (see chapter GPIO) used by TSI, the pin’s mode is
controlled by TSI. Generally, each pin has 3 modes: input, output high and output low.
The mode of a channel pin or a sample pin during a charge-transfer sequence is described
in
Table 26-1. Pin and analog switch state in a charge-transfer sequence
represents a channel pin and PIN1 represents a sample pin, i.e. the charge-transfer FSM take
control of these channels or sample pins’ mode and the states of related analog switches
when the sequence is on-going. When the sequence is in IDLE state, PINMOD bit in
TSI_CTL0 register defines the mode of these pins. Pins that are configured in GPIO used by
TSI but neither sample nor channel in TSI register is called free pins whose mode is defined
by PINMOD bit in TSI_CTL0, too.
26.3.7.
Analog switch (ASW) and I/O hysteresis mode
A channel or sample pin’s analog switch is controlled by charge-transfer sequence when FSM
is running, as shown in
Table 26-1. Pin and analog switch state in a charge-transfer
. When the FSM is IDLE, these pins’ analog switches are controlled by GxPy bits
in TSI_ASW register. All free pin’s analog switches are controlled by GxPy bits too.
TSI takes control of the analog switches when FSM is IDLE, even if these pins are not
configured to be used by TSI in GPIO. The user is able to perform user-defined charge-
transfer sequence by writing GxPy bits to control these analog switches, while controlling pin
mode directly in GPIO.
TSI controller has the highest priority of GPIO. When TSI is enable, this configuration is
available regardless of the GPIO mode, controlled by GPIO registers or other peripherals
Disable the GPIO’s Schmitt trigger hysteresis of TSI Pins by resetting GxPy bit in TSI_PHM
register could improve the system immunity.