8.4.4.3 Synchronous Type 2 Operating Mode
Synchronous type 2 operating mode is only supported on the user card interface. To enter synchronous operating mode, the user card interface goes through the synchronous type 2 activation sequence. Figure 5 shows the synchronous type 2 activation sequence.
CLKIN1 shall be low before the synchronous type 2 activation sequence is initiated. The following bit settings are required to initiate a synchronous type 1 activation sequence.
- ACTIVATION_TYPE (bit [6]; Reg 0x09) = 1
- CARD_TYPE (bit [7]; Reg 0x09) = 1
- START_SYNC (bit [0]; Reg 0x09) = 1
Once synchronous type 2 activation has been initiated, the following sequence of events occur on the user card interface:
- VCCUC, RSTUC, CLKUC, C4, C8 and IOUC are all default low.
- VCC is applied to the VCCUC pin per the SET_VCC_UC bit (bit[7:6]; Reg 0x01).
- A single pulse is applied to CLKUC per the tS2-CLK-HI timing defined in Table 3.
- The C4 line is held low through the VCC ramp.
- The C4 line is released high per the tS2-CLK-C4 timing defined in Table 3.
- After C4 is released CLKUC is controlled by clock settings register (Reg 0x02).
- After VCC is stable, the IOUC line is pulled up to VCC.
- After VCC is stable, C8 reflects value in bit [4] Reg 0x09.
- IOUC is connected to IOMC1 if IO_EN_UC bit (bit[5] Reg 0x01) is set to 1.
- INT_SYNC_COMPLETE bit (Bit[1]; REG 0x41) is set and the INT line is asserted low.
- IOMC1 shall stay pulled up to VDDI , that is, IOMC1 shall not be pulled low until INT is asserted.
- CLKIN1 shall toggle only after INT is asserted.
- RSTUC is controllable by I2C after INT is asserted.
Table 3. Synchronous Type 2 Card Activation Timing Characteristics
|
MIN |
TYP |
MAX |
UNIT |
tS2-VCC-CLK |
5 |
20 |
|
µs |
tS2-CLK-C4 |
14 |
18 |
22 |
µs |
tS2-CLK-HI |
7 |
9 |
11 |
µs |