TDA8029 Datasheet, PDF (46/58 Pages) NXP Semiconductors – Low power single card reader

Philips Semiconductors
Low power single card reader
Product specification
TDA8029
8.17 Deactivation sequence
When the session is completed, the microcontroller resets
bit START (t₁₀). The circuit then executes an automatic
deactivation sequence shown in Fig.13:
• Card reset (pin RST falls LOW) (t₁₁)
• Clock (pin CLK) is stopped LOW (t₁₂)
• Pin I/O falls to 0 V (t₁₃)
• V_CC falls to 0 V with typical 0.17 V/µs slew rate (t₁₄)
• The DC/DC converter is stopped and CLK, RST, V_CC
and I/O become low impedance to GNDC (t₁₅).
t₁₁ = t₁₀ + ³/₆₄T, t₁₂ = t₁₁ + ¹/₂T, t₁₃ = t₁₁ + T,
t₁₄ = t₁₁ + ³/₂T, t₁₅ = t₁₁ + ⁷/₂T.
t_de is the time that V_CC needs for going down to less than
0.4 V.
Automatic emergency deactivation is performed in the
following cases:
• Withdrawal of the card (PRES LOW)
• Overcurrent detection on V_CC (bit PRTL1 set)
• Overcurrent detection on RST (bit PRTL1 set)
• Overheating (bit PTL set)
• Supply too low (bit SUPL set)
• RESET pin active HIGH.
If the reason of the deactivation is a card take off, an
overcurrent or an overheating, then INT0_N is LOW. The
corresponding bit in the hardware status register is set. Bit
START is automatically reset.
If the reason is a supply dropout, then the deactivation
sequence occurs, and a complete reset of the chip is
performed. When the supply will be OK again, then the bit
SUPL will be set in HSR.
handbook, full pagewidth
START
RST
CLK
I/O
VCC
VUP
t10 t11
t12
t13 t14
t15
tde
Fig.13 Deactivation sequence.
FCE685
2003 Oct 30
46