ds26504 Maxim Integrated Products, Inc., ds26504 Datasheet - Page 34

• Manufacturer Part Number: ds26504
• Description: Ds26504 T1/e1/j1/64kcc Bits Element
• Manufacturer: Maxim Integrated Products, Inc.

7.3.1 Power-Up Sequence
The DS26504 contains an on-chip power-up reset function that automatically clears the writeable register
space immediately after power is supplied to the device. The user can issue a chip reset at any time.
Issuing a reset will disrupt signals flowing through the DS26504 until the device is reprogrammed. The
reset can be issued through hardware using the TSTRST pin or through software using the SFTRST
function in the master mode register. The LIRST (LIC2.6) should be toggled from zero to one to reset the
line interface circuitry. (It will take the DS26504 about 40ms to recover from the LIRST bit being
toggled.)
7.3.2 Test Reset Register
Register Name:
Register Description:
Register Address:
Bit #
Name
Default
HW
Mode
Bit 0: Software-Issued Reset (SFTRST). A zero-to-one transition causes the register space in the DS26504 to be cleared. A
reset clears all configuration and status registers. The bit automatically clears itself when the reset has completed.
Bits 1, 2, 3, 6, 7: Unused, must be set = 0 for proper operation.
Bits 4 and 5: Test Mode Bits (TEST0 and TEST1). Test modes are used to force the output pins of the DS26504 into known
states. This can facilitate the checkout of assemblies during the manufacturing process and also be used to isolate devices from
shared buses.
TEST1
0
0
1
1
TEST0
—
X
7
0
0
1
0
1
Operate normally
Force all output pins into three-state (including all I/O pins and parallel port pins)
Force all output pins low (including all I/O pins except parallel port pins)
Force all output pins high (including all I/O pins except parallel port pins)
—
TSTRREG
Test Reset Register
00h
X
6
0
TEST1
X
5
0
TEST0
EFFECT ON OUTPUT PINS
X
4
0
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—
X
3
0
—
X
2
0
DS26504 T1/E1/J1/64KCC BITS Element
—
X
1
0
SFTRST
X
0
0