
MT9071
Preliminary Information
56
A dedicated multiframe boundary pin is included which provides the user the option of setting the multiframe
boundaries with an external device. Refer to the TxMF pin description and to the CRC-4 and CAS sections for
details.
7.6
Reset Operation (RESET, TRST Pins)
On initial power up, a hard reset must be done using both the RESET pin and the TRST pin. A valid reset
condition requires both of these inputs to be held low for a minimum of 100ns. These inputs should be set to
zero during initial power up, then set to one.
After initial power up, the MT9071 can be reset using the hardware pin RESET, or the control register bit RSTC
(see Table 70 - T1 & E1 Global Mode Control - R/W Address 900). In addition, individual transceivers within the
MT9071 may be reset with the control register bit RST (see Table 178 - T1 Interrupt and I/O Control - R/W
Address YF1 and Table 85 - E1 DL, CCS, CAS and Other Control - R/W Address Y03). Note that the common
control (global) registers can only be reset with RESET pin or the RSTC bit. When the device emerges from its
reset state it will begin to function with default settings (see Table 13 - Reset Default Status). A reset operation
takes 1 full frame (125 us) to complete.
7.7
Control Pins
7.7.1
Transmit AIS Operation (TAIS Pin)
The TAIS pin allows all four transceivers of the MT9071 to transmit an all ones signal (AIS) at the TTIP and
TRNG output pins from the point of power-up, without the need to write to any control registers. During this
time the IRQ pin is in a high impedance state. After the interface has been initialized normal operation can take
place by making TAIS high.
7.7.2
IEEE 1149.1-1990 Test Access Port (TAP)
Five signals (TDI, TDO, TMS, TCK & TRST) make up the Test Access Port (TAP) of the IEEE 1149.1-1990
Standard Test Port and Boundary-Scan Architecture. The TAP provides access to test support functions built
into the MT9071. The TAP is also referred to as a JTAG (Joint Test Action Group) port, see Section 8.0 JTAG
Operation.
Function
Status
Mode T1 or E1
System Bus (Backplane)
Counters
Counter Latches
Interrupts
Per Timeslot Control Buffer
Loopbacks
Error Insertion
CAS ABCD Bit Debounce
HDLC
T1
2.048Mb/s
cleared
cleared
all unmasked but suspended and cleared
All locations cleared
deactivated
deactivated
deactivated
deactivated
Table 13 - Reset Default Status