TMS320F2809, TMS320F2808, TMS320F2806
TMS320F2802, TMS320F2801, UCD9501
TMS320C2802, TMS320C2801, and TMS320F2801x DSPs
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SPRS230H–OCTOBER 2003–REVISED JUNE 2006
Table 6-13. Reset (XRS) Timing Requirements
MIN
8tc(OSCCLK)
8tc(OSCCLK)
NOM
MAX
UNIT
cycles
cycles
(1)
tw(RSL1)
Pulse duration, stable XCLKIN to XRS high
Pulse duration, XRS low
tw(RSL2)
tw(WDRS)
td(EX)
Warm reset
Pulse duration, reset pulse generated by
watchdog
512tc(OSCCLK)
cycles
Delay time, address/data valid after XRS high
Oscillator start-up time
32tc(OSCCLK)
10
cycles
ms
(2)
tOSCST
1
th(boot-mode)
Hold time for boot-mode pins
200tc(OSCCLK)
cycles
(1) In addition to the tw(RSL1) requirement, XRS has to be low at least for 1 ms after VDD reaches 1.5 V.
(2) Dependent on crystal/resonator and board design.
XCLKIN
X1/X2
OSCCLK/8
XCLKOUT
XRS
User-Code Dependent
OSCCLK * 5
t
w(RSL2)
User-Code Execution Phase
t
d(EX)
Address/Data/
Control
(Don’t Care)
User-Code Execution
(Internal)
(A)
t
Boot-ROM Execution Starts
GPIO Pins as Input
h(boot-mode)
Boot-Mode
Pins
Peripheral/GPIO Function
User-Code Dependent
Peripheral/GPIO Function
User-Code Execution Starts
I/O Pins
GPIO Pins as Input (State Depends on Internal PU/PD)
User-Code Dependent
A. After reset, the Boot ROM code samples BOOT Mode pins. Based on the status of the Boot Mode pin, the boot code
branches to destination memory or boot code function. If Boot ROM code executes after power-on conditions (in
debugger environment), the Boot code execution time is based on the current SYSCLKOUT speed. The
SYSCLKOUT will be based on user environment and could be with or without PLL enabled.
Figure 6-6. Warm Reset
Figure 6-7 shows an example for the effect of writing into PLLCR register. In the first phase, PLLCR =
0x0004 and SYSCLKOUT = OSCCLK x 2. The PLLCR is then written with 0x0008. Right after the PLLCR
register is written, the PLL lock-up phase begins. During this phase, SYSCLKOUT = OSCCLK/2. After the
PLL lock-up is complete (which takes 131072 OSCCLK cycles), SYSCLKOUT reflects the new operating
frequency, OSCCLK x 4.
Electrical Specifications
101
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